[camera] Stable release for null safety. (flutter#3641)

Stable NNBD release for the camera package.

With this PR I also migrated the example App to sound null safe.

packages/camera/camera/CHANGELOG.md

@@ -1,18 +1,9 @@
-## 0.8.0-nullsafety.3
-
-* Updates the example code listed in the [README.md](README.md), so it runs without errors when you simply copy/ paste it into a Flutter App.
-
-## 0.8.0-nullsafety.2
+## 0.8.0
 
+* Stable null safety release.
 * Solved delay when using the zoom feature on iOS.
-
-## 0.8.0-nullsafety.1
-
 * Added a timeout to the pre-capture sequence on Android to prevent crashes when the camera cannot get a focus.
-
-## 0.8.0-nullsafety
-
-* Migrated to null safety.
+* Updates the example code listed in the [README.md](README.md), so it runs without errors when you simply copy/ paste it into a Flutter App.
 
 ## 0.7.0+4
 

packages/camera/camera/example/integration_test/camera_test.dart

@@ -1,3 +1,10 @@
+// Copyright 2019, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// TODO(mvanbeusekom): Remove this once flutter_driver supports null safety.
+// https://github.com/flutter/flutter/issues/71379
+// @dart = 2.9
 import 'dart:async';
 import 'dart:io';
 import 'dart:ui';