reference apple sign in plugin from google sign in plugin (#2743)

packages/google_sign_in/google_sign_in/CHANGELOG.md

diff --git a/packages/google_sign_in/google_sign_in/CHANGELOG.md b/packages/google_sign_in/google_sign_in/CHANGELOG.md
index b3c3955..8fbba49 100644
--- a/packages/google_sign_in/google_sign_in/CHANGELOG.md
+++ b/packages/google_sign_in/google_sign_in/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.5.1
+
+* Add note on Apple sign in requirement in README.
+
 ## 4.5.0
 
 * Add support for getting `serverAuthCode`.

packages/google_sign_in/google_sign_in/README.md

diff --git a/packages/google_sign_in/google_sign_in/README.md b/packages/google_sign_in/google_sign_in/README.md
index f9e8415..fc87717 100755
--- a/packages/google_sign_in/google_sign_in/README.md
+++ b/packages/google_sign_in/google_sign_in/README.md
@@ -49,6 +49,17 @@
 <!-- End of the Google Sign-in Section -->
 ```
 
+### iOS additional requirement
+
+Note that according to https://developer.apple.com/sign-in-with-apple/get-started,
+starting June 30, 2020, apps that use login services must also offer a "Sign in
+with Apple" option when submitting to the Apple App Store.
+
+Consider also using an Apple sign in plugin from pub.dev.
+
+The Flutter Favorite [sign_in_with_apple](https://pub.dev/packages/sign_in_with_apple)
+plugin could be an option.
+
 ## Usage
 
 ### Import the package

packages/google_sign_in/google_sign_in/pubspec.yaml

diff --git a/packages/google_sign_in/google_sign_in/pubspec.yaml b/packages/google_sign_in/google_sign_in/pubspec.yaml
index b82a2bd..8e52033 100644
--- a/packages/google_sign_in/google_sign_in/pubspec.yaml
+++ b/packages/google_sign_in/google_sign_in/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Flutter plugin for Google Sign-In, a secure authentication system
   for signing in with a Google account on Android and iOS.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in
-version: 4.5.0
+version: 4.5.1
 
 flutter:
   plugin: