Some problems were found with the configuration of task ':app:compileFlutterBuildDebug' (type 'FlutterTask'). - Type 'FlutterTask' property 'assets' is missing an input or output annotation. code example

Example: Some problems were found with the configuration of task ':app:compileFlutterBuildRelease' (type 'FlutterTask'). Type 'FlutterTask' property 'assets' is missing an input or output annotation.

At the moment (20/05/2021) there are issues with gradle 7 and flutter 2.x.x
   You programme should run after downgrading gradle to version 6.x-all
   
 Head on to your project dir (andriod>gradle>wrapper>gradle-wrapper.properties)
   Open the file and replace 7.0-all with 6.7-all