added readme info for the optional AdSupport.framework + libAdIdAccess.a
added readme info for the optional AdSupport.framework + libAdIdAccess.a

rdesai40/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,mmiani/react-native-google-analytics-bridge,rdesai40/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge,idehub/react-native-google-analytics-bridge