v2.1.0

• Please refer to https://fzyzcjy.github.io/flutter_rust_bridge/guides/miscellaneous/whats-new for what's changed in V2.
• Add the ability to generate plugins from the CLI tool #2144 (thanks @mcmah309)
• Fix codegen halt when having boxed trait objects #2180
• Add attribute #[frb(dart_async)] #2181
• Fix Dart closures cannot be encoded when using the new Dart JS interop #2191
• Expose Rust executor's async runtime for customization #2151
• Generate methods of Default trait #2150
• Automatically rename function names to avoid keyword conflict #2150
• Improve parsing trait impl in third party crates #2150
• Support more attributes #2140
• Fix generated use statement pointing to self #2140
• Fix linter warning avoid_return_types_on_setters #2140
• Reduce number of generated files #2140
• Add default_dart_async configuration option #2139
• Handle root module scenario in pub use transformer #2124
• Improve hints when fails to parse a struct or enum #2124