Update authentication.md
Update authentication.md
devshackio/react-native-firestack,devshackio/react-native-firestack,sraka1/react-native-firestack,devshackio/react-native-firestack,sraka1/react-native-firestack,sraka1/react-native-firestack,sraka1/react-native-firestack,devshackio/react-native-firestack