flutter pub add firebase_ui_auth
flutter pub add firebase_ui_oauth_apple
flutter pub add firebase_ui_oauth_google
flutter pub add firebase_ui_auth
import 'package:google_sign_in/google_sign_in.dart';
Initialize GoogleSignIn with the scopes you want:
GoogleSignIn _googleSignIn = GoogleSignIn(
scopes: [
'email',
'https://www.googleapis.com/auth/contacts.readonly',
],
);