Plugin example seems to be broken in v0.4.0

[alexcmgit]

The plugin example seems to be broken in v0.4.0

[jona@jona example]$ flutter run
Running "flutter pub get" in example...                          1.123ms
Launching lib/main.dart on  in debug mode...
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/03 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/03 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/03 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: unexpected element (uri:"", local:"base-extension"). Expected elements are <{}codename>,<{}layoutlib>,<{}api-level>
lib/main.dart:2:8: Error: Error when reading 'lib/screens/persisted_uris/persisted_uri_list.dart': No such file or directory
import 'screens/persisted_uris/persisted_uri_list.dart';
       ^
lib/main.dart:17:36: Error: Method not found: 'PersistedUriList'.
    return const MaterialApp(home: PersistedUriList());
                                   ^^^^^^^^^^^^^^^^


FAILURE: Build failed with an exception.

* Where:
Script '/opt/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 1156

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command '/opt/flutter/bin/flutter'' finished with non-zero exit value 1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 11s
Running Gradle task 'assembleDebug'...                             11,7s
Exception: Gradle task assembleDebug failed with exit code 1

Originally posted by @jfaltis in #61 (comment)

[alexcmgit]

Fixed by #72.

[alexcmgit]

@all-contributors add jfaltis for bug.