Fix copyright notice

Author: swift-kim

packages/path_provider/example/integration_test/path_provider_test.dart

@@ -1,6 +1,6 @@
-// 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.
+// Copyright 2019 the Chromium project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
 import 'dart:async';
 

packages/path_provider/example/test_driver/integration_test.dart

@@ -1,6 +1,6 @@
-// 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.
+// Copyright 2019 the Chromium project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:convert';