update version

Update Readme.md

21.2.2 add command attribute transfer (#15)

* Add_MvvmLight_Support

* Add mvvm light tests + fix relayCommand namespace

* remove KeepTargetAlive command property + refactoring

* Refactoring

* fix format

* Add command attribute generation

* refactoring

* Refactoring

fix WinUI demo

Update Readme.md

Added ParseOptions for attribute generation