feat(#64): Upgraded example and plugin library to use the new GPA 8 s…

[devaronius]

In Flutter 3.16, support was added for applying these plugins with Gradle's declarative plugins {} block (also called the Plugin DSL) and it is now the recommended approach. Since Flutter 3.16, projects generated with flutter create use the Plugin DSL to apply Gradle plugins. Projects created with versions of Flutter prior to 3.16 need to be migrated manually.

https://docs.flutter.dev/release/breaking-changes/flutter-gradle-plugin-apply

Solution:

• [#64] upgraded GPA (Android Gradle Plugin) to version 8 to comply to deprication of the old flutter gradle implementation.

• [#64] Plugin now requires the following:

  • Flutter >=3.19.0
  • Dart >=3.3.0
  • compileSDK 33 for Android part
  • Java 17 for Android part
  • Gradle 8.0 for Android part