mockor library Null safety

Classes

GenerateMocker
the annotation should be placed on your global mock method:
GenerateMocktailFallbackValues
generate method with registerFallbackValues calls, this is needed to make the any() function work in mocktail](https://pub.dev/packages/mocktail).

Exceptions / Errors

MissingFutureVoidStubException
MissingNullStubException