[google_sign_in_web] Add empty podspec to plugin. (#2316)

Add an empty podspec file, so this plugin doesn't break compilation on IOS.

This should fix https://github.com/flutter/flutter/issues/45571
diff --git a/packages/google_sign_in/google_sign_in_web/CHANGELOG.md b/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
index f24bcf5..b2d801e 100644
--- a/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
+++ b/packages/google_sign_in/google_sign_in_web/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.8.1
+
+* Add podspec to enable compilation on iOS.
+
 ## 0.8.0
 
 * Flutter for web initial release
\ No newline at end of file
diff --git a/packages/google_sign_in/google_sign_in_web/ios/google_sign_in_web.podspec b/packages/google_sign_in/google_sign_in_web/ios/google_sign_in_web.podspec
new file mode 100644
index 0000000..5e19217
--- /dev/null
+++ b/packages/google_sign_in/google_sign_in_web/ios/google_sign_in_web.podspec
@@ -0,0 +1,21 @@
+#
+# To learn more about a Podspec see http://guides.cocoapods.org/syntax/podspec.html
+#
+Pod::Spec.new do |s|
+    s.name             = 'google_sign_in_web'
+    s.version          = '0.8.1'
+    s.summary          = 'No-op implementation of google_sign_in_web web plugin to avoid build issues on iOS'
+    s.description      = <<-DESC
+  temp fake google_sign_in_web plugin
+                         DESC
+    s.homepage         = 'https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in_web'
+    s.license          = { :file => '../LICENSE' }
+    s.author           = { 'Flutter Team' => 'flutter-dev@googlegroups.com' }
+    s.source           = { :path => '.' }
+    s.source_files = 'Classes/**/*'
+    s.public_header_files = 'Classes/**/*.h'
+    s.dependency 'Flutter'
+  
+    s.ios.deployment_target = '8.0'
+  end
+  
\ No newline at end of file
diff --git a/packages/google_sign_in/google_sign_in_web/pubspec.yaml b/packages/google_sign_in/google_sign_in_web/pubspec.yaml
index 0c33fe4..ebf20f0 100644
--- a/packages/google_sign_in/google_sign_in_web/pubspec.yaml
+++ b/packages/google_sign_in/google_sign_in_web/pubspec.yaml
@@ -3,7 +3,7 @@
   for signing in with a Google account on Android, iOS and Web.
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in_web
-version: 0.8.0
+version: 0.8.1
 
 flutter:
   plugin: