Export SignInOption from interface since it is used in the frontend (flutter#2350)

Author: mehmetf

packages/google_sign_in/google_sign_in/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.0.15
+
+* Export SignInOption from interface since it is used in the frontend as a type.
+
 ## 4.0.14
 
 * Port plugin code to use the federated Platform Interface, instead of a MethodChannel directly.

packages/google_sign_in/google_sign_in/lib/google_sign_in.dart

@@ -10,6 +10,8 @@ import 'package:google_sign_in_platform_interface/google_sign_in_platform_interf
 
 import 'src/common.dart';
 
+export 'package:google_sign_in_platform_interface/google_sign_in_platform_interface.dart'
+    show SignInOption;
 export 'src/common.dart';
 export 'widgets.dart';
 

packages/google_sign_in/google_sign_in/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Google Sign-In, a secure authentication system
   for signing in with a Google account on Android and iOS.
 author: Flutter Team <[email protected]>
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in
-version: 4.0.14
+version: 4.0.15
 
 flutter:
   plugin: