[Enhancement] pub.dev scores

[alexmercerind]

Now that package:media_kit is available on pub.dev, I'm noticing that we're losing few scores.
From what I've seen so far, primarily due to:

• Missing example(s) in various packages.
• Having too short description in pubspec.yaml of various packages.

A solid 140/140 on all packages will be good to have. Current scores:

• https://pub.dev/packages/media_kit
• https://pub.dev/packages/media_kit_libs_ios_video
• https://pub.dev/packages/media_kit_libs_linux
• https://pub.dev/packages/media_kit_libs_macos_video
• https://pub.dev/packages/media_kit_libs_windows_audio
• https://pub.dev/packages/media_kit_libs_windows_video
• https://pub.dev/packages/media_kit_native_event_loop
• https://pub.dev/packages/media_kit_video

The 'Package layout convention' page suggests that we can have examples at following places. It is important to consider because few of the packages don't have any Dart code in them (at all) & only native implementation or build steps.

• example/example[.md]
• example[/lib]/main.dart
• example[/lib]/package_name.dart
• example[/lib]/package_name_example.dart
• example[/lib]/example.dart
• example/README[.md]

[birros]

And perhaps some screenshots too.

[alexmercerind]

All packages are 140/140 now.