chore: use minSdk=23 for auth, and minSdk=21 for other modules#2196

thatfiredev merged 2 commits intoversion-9.1.0-devfirebase/FirebaseUI-Android:version-9.1.0-devfrom

rpf/decouple-minSdkfirebase/FirebaseUI-Android:rpf/decouple-minSdkCopy head branch name to clipboard