[webview_flutter] release null safety to stable(#3619)

Author: Chris Yang

packages/webview_flutter/CHANGELOG.md

@@ -1,31 +1,13 @@
-## 2.0.0-nullsafety.6
+## 2.0.0
 
+* Migration to null-safety.
 * Added support for progress tracking.
-
-## 2.0.0-nullsafety.5
-
 * Add section to the wiki explaining how to use Material components.
-
-## 2.0.0-nullsafety.4
-
 * Update integration test to workaround an iOS 14 issue with `evaluateJavascript`.
-
-## 2.0.0-nullsafety.3
-
 * Fix `onWebResourceError` on iOS.
-
-## 2.0.0-nullsafety.2
-
 * Fix outdated links across a number of markdown files ([#3276](https://github.com/flutter/plugins/pull/3276))
-
-## 2.0.0-nullsafety.1
-
 * Added `allowsInlineMediaPlayback` property.
 
-## 2.0.0-nullsafety
-
-* Migration to null-safety.
-
 ## 1.0.8
 
 * Update Flutter SDK constraint.

packages/webview_flutter/example/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_example
 description: Demonstrates how to use the webview_flutter plugin.
 
 environment:
-  sdk: ">=2.12.0-0 <3.0.0"
+  sdk: ">=2.12.0-259.9.beta <3.0.0"
 
 dependencies:
   flutter:
@@ -22,7 +22,7 @@ dev_dependencies:
     sdk: flutter
   integration_test:
     path: ../../integration_test
-  pedantic: ^1.8.0
+  pedantic: ^1.10.0
 
 flutter:
   uses-material-design: true

packages/webview_flutter/pubspec.yaml

@@ -1,10 +1,10 @@
 name: webview_flutter
 description: A Flutter plugin that provides a WebView widget on Android and iOS.
-version: 2.0.0-nullsafety.5
 homepage: https://github.com/flutter/plugins/tree/master/packages/webview_flutter
+version: 2.0.0
 
 environment:
-  sdk: ">=2.12.0-0 <3.0.0"
+  sdk: ">=2.12.0-259.9.beta <3.0.0"
   flutter: ">=1.22.0"
 
 dependencies:
@@ -16,7 +16,7 @@ dev_dependencies:
     sdk: flutter
   flutter_driver:
     sdk: flutter
-  pedantic: ^1.10.0-nullsafety.1
+  pedantic: ^1.10.0
 
 flutter:
   plugin: