Update release schedule documentation (#10827)
Update release schedule documentation (#10827)

* expand on release schedule

* address bpaduch's review comments

keithwrightbos/amphtml,luciancrasovan/amphtml,taboola/amphtml,rajkumarsrk/amphtml,cvializ/amphtml,media-net/amphtml,media-net/amphtml,gumgum/amphtml,smartadserver/amphtml,yandex-pcode/amphtml,jridgewell/amphtml,keithwrightbos/amphtml,engtat/amphtml,ampproject/amphtml,media-net/amphtml,src-code/amphtml,zhucl/amphtml,keithwrightbos/amphtml,nexxtv/amphtml,alanorozco/amphtml,prateekbh/amphtml,ampproject/amphtml,cory-work/amphtml,jridgewell/amphtml,rajkumarsrk/amphtml,erwinmombay/amphtml,zhucl/amphtml,yieldmo/amphtml,rsimha-amp/amphtml,kixer-com/amphtml,prateekbh/amphtml,shawnbuso/amphtml,tlong2/amphtml,sebastianbenz/amphtml,prateekbh/amphtml,dotandads/amphtml,yieldbot/amphtml,sharethrough/amphtml,jpettitt/amphtml,danielrozenberg/amphtml,yandex-pcode/amphtml,techhtml/amphtml,prateekbh/amphtml,yandex-pcode/amphtml,mhc-gh/amphtml,clawr/amphtml,alanorozco/amphtml,smartadserver/amphtml,comScore/amphtml,ampproject/amphtml,luciancrasovan/amphtml,donttrustthisbot/amphtml,yieldmo/amphtml,cory-work/amphtml,shawnbuso/amphtml,engtat/amphtml,alanorozco/amphtml,sharethrough/amphtml,ampproject/amphtml,jridgewell/amphtml,ampproject/amphtml,luciancrasovan/amphtml,cory-work/amphtml,arealit/amphtml,jmadler/amphtml,camelburrito/amphtml,shawnbuso/amphtml,adup-tech/amphtml,adup-tech/amphtml,arealit/amphtml,kamtschatka/amphtml,lannka/amphtml,tlong2/amphtml,lannka/amphtml,laterpay/amphtml,camelburrito/amphtml,widespace-os/amphtml,shawnbuso/amphtml,clawr/amphtml,sriramkrish85/amphtml,Gregable/amphtml,cory-work/amphtml,camelburrito/amphtml,zhucl/amphtml,alanorozco/amphtml,honeybadgerdontcare/amphtml,dotandads/amphtml,koshka/amphtml,luciancrasovan/amphtml,gumgum/amphtml,zhangsu/amphtml,tlong2/amphtml,rsimha-amp/amphtml,alanorozco/amphtml,kixer-com/amphtml,mhc-gh/amphtml,dotandads/amphtml,powdercloud/amphtml,adup-tech/amphtml,mhc-gh/amphtml,wjfang/amphtml,bpaduch/amphtml,camelburrito/amphtml,voyagegroup/amphtml,sriramkrish85/amphtml,zhangsu/amphtml,zhangsu/amphtml,pedjoni8/amphtml,zhangsu/amphtml,luciancrasovan/amphtml,danielrozenberg/amphtml,bpaduch/amphtml,jmadler/amphtml,ADITION/amphtml,taboola/amphtml,lannka/amphtml,honeybadgerdontcare/amphtml,Gregable/amphtml,honeybadgerdontcare/amphtml,arealit/amphtml,honeybadgerdontcare/amphtml,comScore/amphtml,cory-work/amphtml,BenDz/amphtml,adiant/amphtml,yieldmo/amphtml,sriramkrish85/amphtml,arealit/amphtml,zhucl/amphtml,chaveznvg/amphtml,widespace-os/amphtml,jmadler/amphtml,kixer-com/amphtml,voyagegroup/amphtml,keithwrightbos/amphtml,bpaduch/amphtml,aghassemi/amphtml,BenDz/amphtml,jpettitt/amphtml,zhouyx/amphtml,zhouyx/amphtml,engtat/amphtml,zhucl/amphtml,yieldbot/amphtml,bpaduch/amphtml,sebastianbenz/amphtml,nexxtv/amphtml,zhangsu/amphtml,cvializ/amphtml,taboola/amphtml,danielrozenberg/amphtml,gumgum/amphtml,rajkumarsrk/amphtml,voyagegroup/amphtml,jpettitt/amphtml,voyagegroup/amphtml,comScore/amphtml,media-net/amphtml,media-net/amphtml,yieldbot/amphtml,ADITION/amphtml,media-net/amphtml,widespace-os/amphtml,pedjoni8/amphtml,clawr/amphtml,yieldbot/amphtml,danielrozenberg/amphtml,clawr/amphtml,taboola/amphtml,yieldmo/amphtml,danielrozenberg/amphtml,media-net/amphtml,Gregable/amphtml,voyagegroup/amphtml,adup-tech/amphtml,techhtml/amphtml,yandex-pcode/amphtml,BenDz/amphtml,ampproject/amphtml,bpaduch/amphtml,camelburrito/amphtml,comScore/amphtml,laterpay/amphtml,kixer-com/amphtml,powdercloud/amphtml,chaveznvg/amphtml,alanorozco/amphtml,tlong2/amphtml,lannka/amphtml,danielrozenberg/amphtml,keithwrightbos/amphtml,BenDz/amphtml,bpaduch/amphtml,mhc-gh/amphtml,mhc-gh/amphtml,widespace-os/amphtml,zhouyx/amphtml,yieldmo/amphtml,sriramkrish85/amphtml,donttrustthisbot/amphtml,rajkumarsrk/amphtml,sriramkrish85/amphtml,tlong2/amphtml,arealit/amphtml,shawnbuso/amphtml,keithwrightbos/amphtml,gumgum/amphtml,smartadserver/amphtml,powdercloud/amphtml,prateekbh/amphtml,arealit/amphtml,luciancrasovan/amphtml,danielrozenberg/amphtml,dotandads/amphtml,honeybadgerdontcare/amphtml,adup-tech/amphtml,BenDz/amphtml,erwinmombay/amphtml,bpaduch/amphtml,sebastianbenz/amphtml,koshka/amphtml,kixer-com/amphtml,aghassemi/amphtml,cvializ/amphtml,wjfang/amphtml,koshka/amphtml,chaveznvg/amphtml,cvializ/amphtml,ampproject/amphtml,pedjoni8/amphtml,koshka/amphtml,nexxtv/amphtml,zhouyx/amphtml,smartadserver/amphtml,dotandads/amphtml,src-code/amphtml,camelburrito/amphtml,laterpay/amphtml,wjfang/amphtml,rajkumarsrk/amphtml,wjfang/amphtml,alanorozco/amphtml,powdercloud/amphtml,arealit/amphtml,laterpay/amphtml,sharethrough/amphtml,rsimha-amp/amphtml,rajkumarsrk/amphtml,Gregable/amphtml,chaveznvg/amphtml,kixer-com/amphtml,sriramkrish85/amphtml,luciancrasovan/amphtml,zhouyx/amphtml,rajkumarsrk/amphtml,danielrozenberg/amphtml,adiant/amphtml,jpettitt/amphtml,ADITION/amphtml,ampproject/amphtml,vmarteev/amphtml,ADITION/amphtml,jpettitt/amphtml,rsimha-amp/amphtml,cory-work/amphtml,kixer-com/amphtml,adiant/amphtml,vmarteev/amphtml,clawr/amphtml,taboola/amphtml,tlong2/amphtml,techhtml/amphtml,donttrustthisbot/amphtml,erwinmombay/amphtml,widespace-os/amphtml,camelburrito/amphtml,kamtschatka/amphtml,comScore/amphtml,engtat/amphtml,donttrustthisbot/amphtml,adiant/amphtml,clawr/amphtml,powdercloud/amphtml,zhangsu/amphtml,jridgewell/amphtml,techhtml/amphtml,yieldbot/amphtml,jpettitt/amphtml,yandex-pcode/amphtml,vmarteev/amphtml,zhucl/amphtml,media-net/amphtml,jpettitt/amphtml,laterpay/amphtml,vmarteev/amphtml,widespace-os/amphtml,jridgewell/amphtml,kamtschatka/amphtml,voyagegroup/amphtml,engtat/amphtml,yandex-pcode/amphtml,powdercloud/amphtml,gumgum/amphtml,gumgum/amphtml,src-code/amphtml,zhouyx/amphtml,prateekbh/amphtml,koshka/amphtml,pedjoni8/amphtml,Gregable/amphtml,rsimha-amp/amphtml,chaveznvg/amphtml,wjfang/amphtml,keithwrightbos/amphtml,laterpay/amphtml,kamtschatka/amphtml,cvializ/amphtml,jridgewell/amphtml,aghassemi/amphtml,Gregable/amphtml,voyagegroup/amphtml,sebastianbenz/amphtml,kamtschatka/amphtml,jmadler/amphtml,techhtml/amphtml,sebastianbenz/amphtml,engtat/amphtml,jmadler/amphtml,aghassemi/amphtml,ADITION/amphtml,pedjoni8/amphtml,comScore/amphtml,jridgewell/amphtml,lannka/amphtml,nexxtv/amphtml,erwinmombay/amphtml,smartadserver/amphtml,wjfang/amphtml,Gregable/amphtml,src-code/amphtml,vmarteev/amphtml,mhc-gh/amphtml,erwinmombay/amphtml,comScore/amphtml,zhucl/amphtml,honeybadgerdontcare/amphtml,erwinmombay/amphtml,clawr/amphtml,koshka/amphtml,adiant/amphtml,yieldbot/amphtml,vmarteev/amphtml,yieldmo/amphtml,pedjoni8/amphtml,donttrustthisbot/amphtml,shawnbuso/amphtml,src-code/amphtml,chaveznvg/amphtml,cvializ/amphtml,sharethrough/amphtml,vmarteev/amphtml,jmadler/amphtml,adiant/amphtml,jpettitt/amphtml,nexxtv/amphtml,yandex-pcode/amphtml,taboola/amphtml,shawnbuso/amphtml,adup-tech/amphtml,kamtschatka/amphtml,nexxtv/amphtml,donttrustthisbot/amphtml,adiant/amphtml,cory-work/amphtml,dotandads/amphtml,techhtml/amphtml,sebastianbenz/amphtml,aghassemi/amphtml,src-code/amphtml,mhc-gh/amphtml,BenDz/amphtml,mhc-gh/amphtml,engtat/amphtml,sharethrough/amphtml,wjfang/amphtml,donttrustthisbot/amphtml,yieldmo/amphtml,sharethrough/amphtml,zhouyx/amphtml,taboola/amphtml,rsimha-amp/amphtml,powdercloud/amphtml,lannka/amphtml,smartadserver/amphtml,gumgum/amphtml,rsimha-amp/amphtml,prateekbh/amphtml,alanorozco/amphtml,aghassemi/amphtml,nexxtv/amphtml,Gregable/amphtml,lannka/amphtml,honeybadgerdontcare/amphtml