[google_sign_in] fix registration links (flutter#3859)

Fixes flutter/flutter#81847

Author: kevmoo

packages/google_sign_in/google_sign_in/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Fixed links in `README.md`.
+
 ## 5.0.2
 
 * Fix flutter/flutter#48602 iOS flow shows account selection, if user is signed in to Google on the device.

packages/google_sign_in/google_sign_in/README.md

@@ -1,34 +1,42 @@
-# google_sign_in
-
 [![pub package](https://img.shields.io/pub/v/google_sign_in.svg)](https://pub.dev/packages/google_sign_in)
 
 A Flutter plugin for [Google Sign In](https://developers.google.com/identity/).
 
-*Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
+_Note_: This plugin is still under development, and some APIs might not be
+available yet. [Feedback](https://github.com/flutter/flutter/issues) and
+[Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
 ## Android integration
 
-To access Google Sign-In, you'll need to make sure to [register your
-application](https://developers.google.com/mobile/add?platform=android).
+To access Google Sign-In, you'll need to make sure to
+[register your application](https://firebase.google.com/docs/android/setup).
 
 You don't need to include the google-services.json file in your app unless you
 are using Google services that require it. You do need to enable the OAuth APIs
-that you want, using the [Google Cloud Platform API
-manager](https://console.developers.google.com/). For example, if you
-want to mimic the behavior of the Google Sign-In sample app, you'll need to
-enable the [Google People API](https://developers.google.com/people/).
+that you want, using the
+[Google Cloud Platform API manager](https://console.developers.google.com/). For
+example, if you want to mimic the behavior of the Google Sign-In sample app,
+you'll need to enable the
+[Google People API](https://developers.google.com/people/).
 
-Make sure you've filled out all required fields in the console for [OAuth consent screen](https://console.developers.google.com/apis/credentials/consent). Otherwise, you may encounter `APIException` errors.
+Make sure you've filled out all required fields in the console for
+[OAuth consent screen](https://console.developers.google.com/apis/credentials/consent).
+Otherwise, you may encounter `APIException` errors.
 
 ## iOS integration
 
-1. [First register your application](https://developers.google.com/mobile/add?platform=ios).
-2. Make sure the file you download in step 1 is named `GoogleService-Info.plist`.
-3. Move or copy `GoogleService-Info.plist` into the `[my_project]/ios/Runner` directory.
-4. Open Xcode, then right-click on `Runner` directory and select `Add Files to "Runner"`.
+1. [First register your application](https://firebase.google.com/docs/ios/setup).
+2. Make sure the file you download in step 1 is named
+   `GoogleService-Info.plist`.
+3. Move or copy `GoogleService-Info.plist` into the `[my_project]/ios/Runner`
+   directory.
+4. Open Xcode, then right-click on `Runner` directory and select
+   `Add Files to "Runner"`.
 5. Select `GoogleService-Info.plist` from the file manager.
-6. A dialog will show up and ask you to select the targets, select the `Runner` target.
-7. Then add the `CFBundleURLTypes` attributes below into the `[my_project]/ios/Runner/Info.plist` file.
+6. A dialog will show up and ask you to select the targets, select the `Runner`
+   target.
+7. Then add the `CFBundleURLTypes` attributes below into the
+   `[my_project]/ios/Runner/Info.plist` file.
 
 ```xml
 <!-- Put me in the [my_project]/ios/Runner/Info.plist file -->
@@ -51,21 +59,26 @@ Make sure you've filled out all required fields in the console for [OAuth consen
 
 ### 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.
+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.
+The Flutter Favorite
+[sign_in_with_apple](https://pub.dev/packages/sign_in_with_apple) plugin could
+be an option.
 
 ## Usage
 
 ### Import the package
-To use this plugin, follow the [plugin installation instructions](https://pub.dev/packages/google_sign_in#pub-pkg-tab-installing).
+
+To use this plugin, follow the
+[plugin installation instructions](https://pub.dev/packages/google_sign_in#pub-pkg-tab-installing).
 
 ### Use the plugin
+
 Add the following import to your Dart code:
 
 ```dart
@@ -82,6 +95,7 @@ GoogleSignIn _googleSignIn = GoogleSignIn(
   ],
 );
 ```
+
 [Full list of available scopes](https://developers.google.com/identity/protocols/googlescopes).
 
 You can now use the `GoogleSignIn` class to authenticate in your Dart code, e.g.
@@ -98,13 +112,6 @@ Future<void> _handleSignIn() async {
 
 ## Example
 
-Find the example wiring in the [Google sign-in example application](https://github.com/flutter/plugins/blob/master/packages/google_sign_in/google_sign_in/example/lib/main.dart).
-
-## API details
-
-See the [google_sign_in.dart](https://github.com/flutter/plugins/blob/master/packages/google_sign_in/google_sign_in/lib/google_sign_in.dart) for more API details.
-
-## Issues and feedback
+Find the example wiring in the
+[Google sign-in example application](https://github.com/flutter/plugins/blob/master/packages/google_sign_in/google_sign_in/example/lib/main.dart).
 
-Please file [issues](https://github.com/flutter/flutter/issues/new)
-to send feedback or report a bug. Thank you!