Add Swift Package Manager support

[leredirect]

flutter pub get on flutter: 3.44.0 with gamepads: ^0.1.10+2 in pubspec outputs next hint:

The following plugins do not support Swift Package Manager for ios:
  - gamepads_ios
This will become an error in a future version of Flutter. Please contact the plugin maintainers to request Swift
Package Manager adoption.
The following plugins do not support Swift Package Manager for macos:
  - gamepads_darwin
This will become an error in a future version of Flutter. Please contact the plugin maintainers to request Swift
Package Manager adoption.

flutter doctor:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 3.44.0, on macOS 26.5 25F71 darwin-arm64, locale ru-BY)
[✓] Android toolchain - develop for Android devices (Android SDK version 36.1.0)
[✓] Xcode - develop for iOS and macOS (Xcode 26.4.1)
[✓] Chrome - develop for the web
[✓] Connected device (3 available)
[✓] Network resources