Update dependencies and version to 2.2.0 with executable addition

[tegarnugroho]

This pull request updates the package for compatibility with Flutter 3.35.7+ by upgrading the dart_style dependency to version 3.x and making related code and test adjustments. Additionally, it simplifies generated and test code formatting for better readability and maintainability.

Dependency and compatibility updates:

• Updated the dart_style dependency from ^2.3.0 to ^3.0.0 in pubspec.yaml to ensure compatibility with Flutter 3.35.7+ and incremented the package version to 2.2.0. [1] [2] [3]
• Modified code in code_generator.dart to use DartFormatter.latestLanguageVersion as required by dart_style 3.x.

Test and generated code improvements:

• Updated test expectations and generated code to match new formatting conventions from dart_style 3.x, primarily by collapsing multi-line collections and function signatures into single lines for conciseness. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]

Changelog:

• Added a new entry in CHANGELOG.md to document these updates and compatibility improvements.