Speed up npm installs on Travis
Speed up npm installs on Travis

Re: https://github.com/npm/npm/issues/11283
gumgum/amphtml,src-code/amphtml,sortable/amphtml,alanorozco/amphtml,AaronCritchley/amphtml,sortable/amphtml,rlugojr/amphtml,galeksic/amphtml,DAC-f1h-dev/amphtml,Mobusi-ads/amphtml,wjfang/amphtml,triplelift/amphtml,shawnbuso/amphtml,camelburrito/amphtml,yieldmo/amphtml,BenDz/amphtml,AaronCritchley/amphtml,ruturajv-media-net/amphtml,sebastianbenz/amphtml,media-net/amphtml,media-net/amphtml,camelburrito/amphtml,donttrustthisbot/amphtml,triplelift/amphtml,pedjoni8/amphtml,cvializ/amphtml,avimehta/amphtml,taboola/amphtml,laterpay/amphtml,clawr/amphtml,keithwrightbos/amphtml,dvoytenko/amphtml,erwinmombay/amphtml,mlb7687/amphtml,cory-work/amphtml,rifler/amphtml,pietergreyling/amphtml,jpettitt/amphtml,lannka/amphtml,lzanol/amphtml,luciancrasovan/amphtml,criteo-forks/amphtml,media-net/amphtml,chaveznvg/amphtml,ericlindley-g/amphtml,erwinmombay/amphtml,jpettitt/amphtml,cory-work/amphtml,gumgum/amphtml,ithinkihaveacat/amphtml,ithinkihaveacat/amphtml,cvializ/amphtml,tdrl/amphtml,rajkumarsrk/amphtml,cory-work/amphtml,spotxchange/amphtml,jmadler/amphtml,comScore/amphtml,Adtoma/amphtml,lannka/amphtml,tlong2/amphtml,zhouyx/amphtml,rlugojr/amphtml,kixer-com/amphtml,danielrozenberg/amphtml,danielrozenberg/amphtml,alanorozco/amphtml,lzanol/amphtml,Meggin/amphtml,jlucero-contentad/amphtml,kamtschatka/amphtml,gumgum/amphtml,arealit/amphtml,powdercloud/amphtml,luciancrasovan/amphtml,shawnbuso/amphtml,DAC-f1h-dev/amphtml,rifler/amphtml,sebastianbenz/amphtml,vmarteev/amphtml,voyagegroup/amphtml,plista/amphtml,dvoytenko/amphtml,nexxtv/amphtml,rifler/amphtml,avimehta/amphtml,jpettitt/amphtml,danielrozenberg/amphtml,cvializ/amphtml,smartadserver/amphtml,laterpay/amphtml,kmh287/amphtml,nexxtv/amphtml,adiant/amphtml,Lith/amphtml,criteo-forks/amphtml,ColombiaAnalytics/amphtml,rsimha-amp/amphtml,yevheniiminin/amphtml,Adtoma/amphtml,tlong2/amphtml,Lith/amphtml,bpaduch/amphtml,mlb7687/amphtml,Gregable/amphtml,DAC-f1h-dev/amphtml,sortable/amphtml,tdrl/amphtml,widespace-os/amphtml,BenDz/amphtml,fullspeed-sp/amphtml,mkhatib/amphtml,cory-work/amphtml,lannka/amphtml,sklobovskaya/amphtml,zhangsu/amphtml,gumgum/amphtml,yevheniiminin/amphtml,Gregable/amphtml,BenDz/amphtml-atinternet,adiant/amphtml,lannka/amphtml,zhouyx/amphtml,BenDz/amphtml,JuliusThms/amphtml,JuliusThms/amphtml,BrightcoveOS/amphtml,erwinmombay/amphtml,engtat/amphtml,mhc-gh/amphtml,chaveznvg/amphtml,ruturajv-media-net/amphtml,lannka/amphtml,koshka/amphtml,lannka/amphtml,sriramkrish85/amphtml,shawnbuso/amphtml,taboola/amphtml,DarXector/amphtml,ericlindley-g/amphtml,techhtml/amphtml,sharethrough/amphtml,rifler/amphtml,sklobovskaya/amphtml,chaveznvg/amphtml,ithinkihaveacat/amphtml,ADITION/amphtml,luciancrasovan/amphtml,voyagegroup/amphtml,sriramkrish85/amphtml,triplelift/amphtml,DarXector/amphtml,tdrl/amphtml,AaronCritchley/amphtml,DAC-f1h-dev/amphtml,cvializ/amphtml,spotxchange/amphtml,pietergreyling/amphtml,spotxchange/amphtml,kmh287/amphtml,Mobusi-ads/amphtml,loic-seguin/amphtml,prateekbh/amphtml,jridgewell/amphtml,devjsun/amphtml,jpettitt/amphtml,voyagegroup/amphtml,vmarteev/amphtml,camelburrito/amphtml,nexxtv/amphtml,arealit/amphtml,jridgewell/amphtml,ruturajv-media-net/amphtml,DarXector/amphtml,yevheniiminin/amphtml,honeybadgerdontcare/amphtml,Lith/amphtml,zhucl/amphtml,Mobusi-ads/amphtml,kamtschatka/amphtml,fullspeed-sp/amphtml,aghassemi/amphtml,prateekbh/amphtml,arealit/amphtml,vmarteev/amphtml,nathangoulding/amphtml,koshka/amphtml,prateekbh/amphtml,fullspeed-sp/amphtml,yieldmo/amphtml,yieldbot/amphtml,yieldbot/amphtml,widespace-os/amphtml,NataliaLKB/amphtml,mlb7687/amphtml,nekodo/amphtml,triplelift/amphtml,BrightcoveOS/amphtml,Adtoma/amphtml,jdelhommeau/amphtml,src-code/amphtml,kamtschatka/amphtml,jlucero-contentad/amphtml,pedjoni8/amphtml,ADITION/amphtml,dotandads/amphtml,laterpay/amphtml,aghassemi/amphtml,DAC-f1h-dev/amphtml,Re-lM/amphtml,criteo-forks/amphtml,tdrl/amphtml,adiant/amphtml,vmarteev/amphtml,mhc-gh/amphtml,BenDz/amphtml,Mixpo/amphtml,mhc-gh/amphtml,adiant/amphtml,interspacejp/amphtml,alanorozco/amphtml,engtat/amphtml,gumgum/amphtml,engtat/amphtml,criteo-forks/amphtml,adup-tech/amphtml,engtat/amphtml,src-code/amphtml,nathangoulding/amphtml,vmarteev/amphtml,prateekbh/amphtml,loic-seguin/amphtml,DistroScale/amphtml,src-code/amphtml,plista/amphtml,vmarteev/amphtml,Mobusi-ads/amphtml,sklobovskaya/amphtml,ADITION/amphtml,engtat/amphtml,dotandads/amphtml,rajkumarsrk/amphtml,rsimha-amp/amphtml,adup-tech/amphtml,tlong2/amphtml,wjfang/amphtml,bpaduch/amphtml,Mobusi-ads/amphtml,jlucero-contentad/amphtml,yandex-pcode/amphtml,nathangoulding/amphtml,BenDz/amphtml,Adtoma/amphtml,galeksic/amphtml,kixer-com/amphtml,dotandads/amphtml,burtcorp/amphtml,adiant/amphtml,jpettitt/amphtml,sklobovskaya/amphtml,cory-work/amphtml,ruturajv-media-net/amphtml,widespace-os/amphtml,media-net/amphtml,pedjoni8/amphtml,keithwrightbos/amphtml,burtcorp/amphtml,ecoron/amphtml,media-net/amphtml,erwinmombay/amphtml,adtechnology/amphtml,rlugojr/amphtml,erwinmombay/amphtml,engtat/amphtml,nekodo/amphtml,bpaduch/amphtml,mhc-gh/amphtml,burtcorp/amphtml,zhangsu/amphtml,adtechnology/amphtml,adup-tech/amphtml,Lith/amphtml,dvoytenko/amphtml,ColombiaAnalytics/amphtml,jlucero-contentad/amphtml,kixer-com/amphtml,donttrustthisbot/amphtml,devjsun/amphtml,interspacejp/amphtml,triplelift/amphtml,sebastianbenz/amphtml,ruturajv-media-net/amphtml,zhouyx/amphtml,adtechnology/amphtml,honeybadgerdontcare/amphtml,jdelhommeau/amphtml,sriramkrish85/amphtml,spotxchange/amphtml,alanorozco/amphtml,Mixpo/amphtml,pedjoni8/amphtml,yieldmo/amphtml,honeybadgerdontcare/amphtml,clawr/amphtml,taboola/amphtml,lannka/amphtml,alanorozco/amphtml,prateekbh/amphtml,powdercloud/amphtml,interspacejp/amphtml,avimehta/amphtml,rsimha-amp/amphtml,techhtml/amphtml,donttrustthisbot/amphtml,burtcorp/amphtml,wjfang/amphtml,tlong2/amphtml,chaveznvg/amphtml,sklobovskaya/amphtml,yandex-pcode/amphtml,nekodo/amphtml,keithwrightbos/amphtml,luciancrasovan/amphtml,galeksic/amphtml,jlucero-contentad/amphtml,galeksic/amphtml,fullspeed-sp/amphtml,Mixpo/amphtml,jridgewell/amphtml,JuliusThms/amphtml,spotxchange/amphtml,lzanol/amphtml,jmadler/amphtml,avimehta/amphtml,jasti/amphtml,rsimha-amp/amphtml,rlugojr/amphtml,koshka/amphtml,ericlindley-g/amphtml,voyagegroup/amphtml,amoad-amoe/amphtml,amoad-amoe/amphtml,powdercloud/amphtml,spotxchange/amphtml,Gregable/amphtml,donttrustthisbot/amphtml,adup-tech/amphtml,koshka/amphtml,devjsun/amphtml,cory-work/amphtml,techhtml/amphtml,jasti/amphtml,Gregable/amphtml,ecoron/amphtml,jpettitt/amphtml,zhouyx/amphtml,vmarteev/amphtml,adup-tech/amphtml,sriramkrish85/amphtml,lzanol/amphtml,bpaduch/amphtml,NataliaLKB/amphtml,powdercloud/amphtml,tdrl/amphtml,ithinkihaveacat/amphtml,wjfang/amphtml,voyagegroup/amphtml,clawr/amphtml,honeybadgerdontcare/amphtml,sriramkrish85/amphtml,jdelhommeau/amphtml,yieldbot/amphtml,adtechnology/amphtml,danielrozenberg/amphtml,rajkumarsrk/amphtml,cory-work/amphtml,sklobovskaya/amphtml,NataliaLKB/amphtml,avimehta/amphtml,Mixpo/amphtml,AaronCritchley/amphtml,erwinmombay/amphtml,shawnbuso/amphtml,DistroScale/amphtml,mlb7687/amphtml,kamtschatka/amphtml,chaveznvg/amphtml,keithwrightbos/amphtml,arealit/amphtml,rajkumarsrk/amphtml,pietergreyling/amphtml,kixer-com/amphtml,donttrustthisbot/amphtml,honeybadgerdontcare/amphtml,ColombiaAnalytics/amphtml,yieldbot/amphtml,Meggin/amphtml,mkhatib/amphtml,keithwrightbos/amphtml,rsimha-amp/amphtml,widespace-os/amphtml,clawr/amphtml,ampproject/amphtml,BrightcoveOS/amphtml,taboola/amphtml,zhangsu/amphtml,ericlindley-g/amphtml,sortable/amphtml,jridgewell/amphtml,aghassemi/amphtml,nexxtv/amphtml,jdelhommeau/amphtml,bpaduch/amphtml,Mobusi-ads/amphtml,Mixpo/amphtml,pietergreyling/amphtml,laterpay/amphtml,ecoron/amphtml,rajkumarsrk/amphtml,DarXector/amphtml,taboola/amphtml,luciancrasovan/amphtml,Lith/amphtml,bpaduch/amphtml,yevheniiminin/amphtml,zhucl/amphtml,media-net/amphtml,yandex-pcode/amphtml,Adtoma/amphtml,danielrozenberg/amphtml,DarXector/amphtml,donttrustthisbot/amphtml,smartadserver/amphtml,ampproject/amphtml,kmh287/amphtml,src-code/amphtml,BenDz/amphtml,mhc-gh/amphtml,AaronCritchley/amphtml,arealit/amphtml,BrightcoveOS/amphtml,DistroScale/amphtml,amoad-amoe/amphtml,triplelift/amphtml,devjsun/amphtml,comScore/amphtml,kmh287/amphtml,zhucl/amphtml,camelburrito/amphtml,sklobovskaya/amphtml,jasti/amphtml,jmadler/amphtml,yevheniiminin/amphtml,jasti/amphtml,dvoytenko/amphtml,sharethrough/amphtml,sharethrough/amphtml,comScore/amphtml,alanorozco/amphtml,plista/amphtml,jdelhommeau/amphtml,JuliusThms/amphtml,jasti/amphtml,yevheniiminin/amphtml,src-code/amphtml,smartadserver/amphtml,ADITION/amphtml,mkhatib/amphtml,zhucl/amphtml,dotandads/amphtml,Gregable/amphtml,Adtoma/amphtml,alanorozco/amphtml,camelburrito/amphtml,yandex-pcode/amphtml,smartadserver/amphtml,luciancrasovan/amphtml,sharethrough/amphtml,yandex-pcode/amphtml,koshka/amphtml,Mixpo/amphtml,ecoron/amphtml,laterpay/amphtml,NataliaLKB/amphtml,camelburrito/amphtml,burtcorp/amphtml,clawr/amphtml,powdercloud/amphtml,rifler/amphtml,jlucero-contentad/amphtml,techhtml/amphtml,yieldmo/amphtml,ADITION/amphtml,jmadler/amphtml,jpettitt/amphtml,BrightcoveOS/amphtml,DistroScale/amphtml,rlugojr/amphtml,kamtschatka/amphtml,yandex-pcode/amphtml,DarXector/amphtml,media-net/amphtml,kmh287/amphtml,pietergreyling/amphtml,dotandads/amphtml,simplereach/amphtml,nathangoulding/amphtml,Re-lM/amphtml,galeksic/amphtml,rlugojr/amphtml,taboola/amphtml,jpettitt/amphtml,fullspeed-sp/amphtml,jridgewell/amphtml,aghassemi/amphtml,tlong2/amphtml,rsimha-amp/amphtml,pedjoni8/amphtml,danielrozenberg/amphtml,smartadserver/amphtml,simplereach/amphtml,sebastianbenz/amphtml,voyagegroup/amphtml,zhouyx/amphtml,britice/amphtml,Gregable/amphtml,aghassemi/amphtml,comScore/amphtml,arealit/amphtml,devjsun/amphtml,media-net/amphtml,cvializ/amphtml,zhangsu/amphtml,zhouyx/amphtml,gumgum/amphtml,simplereach/amphtml,ampproject/amphtml,smartadserver/amphtml,sortable/amphtml,techhtml/amphtml,amoad-amoe/amphtml,ampproject/amphtml,sharethrough/amphtml,sharethrough/amphtml,ampproject/amphtml,laterpay/amphtml,kmh287/amphtml,pedjoni8/amphtml,jmadler/amphtml,wjfang/amphtml,mlb7687/amphtml,gumgum/amphtml,jdelhommeau/amphtml,lzanol/amphtml,adiant/amphtml,prateekbh/amphtml,britice/amphtml,devjsun/amphtml,lzanol/amphtml,alanorozco/amphtml,comScore/amphtml,jridgewell/amphtml,zhangsu/amphtml,Meggin/amphtml,Gregable/amphtml,dvoytenko/amphtml,keithwrightbos/amphtml,kixer-com/amphtml,wjfang/amphtml,kixer-com/amphtml,zhouyx/amphtml,jmadler/amphtml,honeybadgerdontcare/amphtml,mlb7687/amphtml,loic-seguin/amphtml,BrightcoveOS/amphtml,clawr/amphtml,ColombiaAnalytics/amphtml,techhtml/amphtml,clawr/amphtml,interspacejp/amphtml,mhc-gh/amphtml,BenDz/amphtml-atinternet,ruturajv-media-net/amphtml,Lith/amphtml,avimehta/amphtml,JuliusThms/amphtml,amoad-amoe/amphtml,amoad-amoe/amphtml,BenDz/amphtml-atinternet,criteo-forks/amphtml,yieldmo/amphtml,ericlindley-g/amphtml,widespace-os/amphtml,engtat/amphtml,fullspeed-sp/amphtml,adup-tech/amphtml,nekodo/amphtml,burtcorp/amphtml,rajkumarsrk/amphtml,keithwrightbos/amphtml,bpaduch/amphtml,mkhatib/amphtml,shawnbuso/amphtml,kamtschatka/amphtml,jasti/amphtml,ecoron/amphtml,yieldmo/amphtml,mkhatib/amphtml,sebastianbenz/amphtml,dotandads/amphtml,danielrozenberg/amphtml,DistroScale/amphtml,rsimha-amp/amphtml,mhc-gh/amphtml,britice/amphtml,jridgewell/amphtml,comScore/amphtml,shawnbuso/amphtml,yieldmo/amphtml,Gregable/amphtml,AaronCritchley/amphtml,powdercloud/amphtml,adiant/amphtml,cvializ/amphtml,pietergreyling/amphtml,donttrustthisbot/amphtml,widespace-os/amphtml,nexxtv/amphtml,taboola/amphtml,tdrl/amphtml,ampproject/amphtml,aghassemi/amphtml,ericlindley-g/amphtml,wjfang/amphtml,yieldbot/amphtml,sebastianbenz/amphtml,britice/amphtml,dvoytenko/amphtml,adtechnology/amphtml,DistroScale/amphtml,zhucl/amphtml,interspacejp/amphtml,ecoron/amphtml,zhangsu/amphtml,Re-lM/amphtml,ampproject/amphtml,DAC-f1h-dev/amphtml,camelburrito/amphtml,interspacejp/amphtml,voyagegroup/amphtml,JuliusThms/amphtml,sriramkrish85/amphtml,mhc-gh/amphtml,yieldbot/amphtml,arealit/amphtml,ampproject/amphtml,kixer-com/amphtml,tlong2/amphtml,chaveznvg/amphtml,zhucl/amphtml,Re-lM/amphtml,danielrozenberg/amphtml,luciancrasovan/amphtml,rajkumarsrk/amphtml,honeybadgerdontcare/amphtml,sortable/amphtml,loic-seguin/amphtml,comScore/amphtml,criteo-forks/amphtml,yandex-pcode/amphtml,prateekbh/amphtml,koshka/amphtml,zhucl/amphtml,rifler/amphtml,plista/amphtml,mkhatib/amphtml,nexxtv/amphtml,powdercloud/amphtml,shawnbuso/amphtml,nexxtv/amphtml,adtechnology/amphtml