add .firebase to gitignore (#17690)
add .firebase to gitignore (#17690)


prateekbh/amphtml,dotandads/amphtml,zhangsu/amphtml,alanorozco/amphtml,mhc-gh/amphtml,erwinmombay/amphtml,yieldbot/amphtml,Gregable/amphtml,cory-work/amphtml,honeybadgerdontcare/amphtml,zhouyx/amphtml,jridgewell/amphtml,cory-work/amphtml,jridgewell/amphtml,alanorozco/amphtml,alanorozco/amphtml,erwinmombay/amphtml,danielrozenberg/amphtml,erwinmombay/amphtml,zhangsu/amphtml,kamtschatka/amphtml,tlong2/amphtml,alanorozco/amphtml,src-code/amphtml,cory-work/amphtml,lannka/amphtml,honeybadgerdontcare/amphtml,danielrozenberg/amphtml,ampproject/amphtml,cvializ/amphtml,yieldbot/amphtml,media-net/amphtml,nexxtv/amphtml,BenDz/amphtml,sharethrough/amphtml,koshka/amphtml,yieldbot/amphtml,adup-tech/amphtml,tlong2/amphtml,lannka/amphtml,taboola/amphtml,danielrozenberg/amphtml,Gregable/amphtml,zhouyx/amphtml,nexxtv/amphtml,zhouyx/amphtml,honeybadgerdontcare/amphtml,tlong2/amphtml,ampproject/amphtml,laterpay/amphtml,yandex-pcode/amphtml,honeybadgerdontcare/amphtml,smartadserver/amphtml,alanorozco/amphtml,widespace-os/amphtml,prateekbh/amphtml,smartadserver/amphtml,sharethrough/amphtml,src-code/amphtml,media-net/amphtml,koshka/amphtml,cvializ/amphtml,yieldbot/amphtml,taboola/amphtml,yandex-pcode/amphtml,BenDz/amphtml,rsimha-amp/amphtml,jpettitt/amphtml,sebastianbenz/amphtml,jmadler/amphtml,jpettitt/amphtml,koshka/amphtml,pedjoni8/amphtml,taboola/amphtml,yandex-pcode/amphtml,sebastianbenz/amphtml,smartadserver/amphtml,mhc-gh/amphtml,voyagegroup/amphtml,ampproject/amphtml,lannka/amphtml,chaveznvg/amphtml,prateekbh/amphtml,Gregable/amphtml,laterpay/amphtml,zhangsu/amphtml,koshka/amphtml,techhtml/amphtml,nexxtv/amphtml,jpettitt/amphtml,laterpay/amphtml,chaveznvg/amphtml,Gregable/amphtml,media-net/amphtml,lannka/amphtml,techhtml/amphtml,sebastianbenz/amphtml,dotandads/amphtml,cory-work/amphtml,taboola/amphtml,widespace-os/amphtml,sharethrough/amphtml,lannka/amphtml,jridgewell/amphtml,honeybadgerdontcare/amphtml,voyagegroup/amphtml,src-code/amphtml,lannka/amphtml,widespace-os/amphtml,voyagegroup/amphtml,zhangsu/amphtml,yieldbot/amphtml,yandex-pcode/amphtml,alanorozco/amphtml,jpettitt/amphtml,kamtschatka/amphtml,taboola/amphtml,smartadserver/amphtml,widespace-os/amphtml,Gregable/amphtml,smartadserver/amphtml,dotandads/amphtml,rsimha-amp/amphtml,danielrozenberg/amphtml,jpettitt/amphtml,BenDz/amphtml,nexxtv/amphtml,jpettitt/amphtml,src-code/amphtml,cvializ/amphtml,techhtml/amphtml,adup-tech/amphtml,danielrozenberg/amphtml,media-net/amphtml,taboola/amphtml,ampproject/amphtml,media-net/amphtml,laterpay/amphtml,chaveznvg/amphtml,nexxtv/amphtml,dotandads/amphtml,yandex-pcode/amphtml,tlong2/amphtml,sebastianbenz/amphtml,dotandads/amphtml,mhc-gh/amphtml,cory-work/amphtml,yandex-pcode/amphtml,koshka/amphtml,rsimha-amp/amphtml,rsimha-amp/amphtml,rsimha-amp/amphtml,media-net/amphtml,laterpay/amphtml,mhc-gh/amphtml,prateekbh/amphtml,cory-work/amphtml,cory-work/amphtml,kamtschatka/amphtml,voyagegroup/amphtml,jmadler/amphtml,voyagegroup/amphtml,pedjoni8/amphtml,taboola/amphtml,mhc-gh/amphtml,danielrozenberg/amphtml,honeybadgerdontcare/amphtml,techhtml/amphtml,kamtschatka/amphtml,kamtschatka/amphtml,jmadler/amphtml,src-code/amphtml,voyagegroup/amphtml,jridgewell/amphtml,adup-tech/amphtml,Gregable/amphtml,techhtml/amphtml,prateekbh/amphtml,jmadler/amphtml,chaveznvg/amphtml,pedjoni8/amphtml,media-net/amphtml,adup-tech/amphtml,src-code/amphtml,mhc-gh/amphtml,widespace-os/amphtml,kamtschatka/amphtml,nexxtv/amphtml,jridgewell/amphtml,ampproject/amphtml,zhouyx/amphtml,yandex-pcode/amphtml,dotandads/amphtml,jpettitt/amphtml,prateekbh/amphtml,Gregable/amphtml,sharethrough/amphtml,erwinmombay/amphtml,cvializ/amphtml,ampproject/amphtml,tlong2/amphtml,prateekbh/amphtml,adup-tech/amphtml,zhouyx/amphtml,chaveznvg/amphtml,BenDz/amphtml,BenDz/amphtml,jridgewell/amphtml,mhc-gh/amphtml,sharethrough/amphtml,erwinmombay/amphtml,alanorozco/amphtml,techhtml/amphtml,honeybadgerdontcare/amphtml,mhc-gh/amphtml,zhouyx/amphtml,laterpay/amphtml,pedjoni8/amphtml,voyagegroup/amphtml,rsimha-amp/amphtml,erwinmombay/amphtml,ampproject/amphtml,ampproject/amphtml,widespace-os/amphtml,yieldbot/amphtml,jmadler/amphtml,jridgewell/amphtml,sebastianbenz/amphtml,rsimha-amp/amphtml,cvializ/amphtml,media-net/amphtml,sharethrough/amphtml,sebastianbenz/amphtml,zhangsu/amphtml,lannka/amphtml,koshka/amphtml,danielrozenberg/amphtml,tlong2/amphtml,pedjoni8/amphtml,pedjoni8/amphtml,nexxtv/amphtml,zhangsu/amphtml,jpettitt/amphtml,Gregable/amphtml,jmadler/amphtml,chaveznvg/amphtml,cvializ/amphtml,zhouyx/amphtml,smartadserver/amphtml,alanorozco/amphtml,adup-tech/amphtml,danielrozenberg/amphtml,BenDz/amphtml