Release [super_enum] v0.5.0, [super_enum_generator] v0.6.0

Release Notes:

[Super Enum]

Added support for optional data fields (https://github.com/xsahil03x/super_enum/issues/51)
```
DataField<String>("errorMessage", required: false),
```
Updated equatable to ^1.2.5
Updated meta to ^1.2.3

Part File naming has been changed to filename.super.dart from `filename.g.dart.
Removed all asyncWhenX methods as they were redundant.
Added support for analyzer > 0.40.0 (https://github.com/xsahil03x/super_enum/issues/63)
Added support for optional data fields (https://github.com/xsahil03x/super_enum/issues/51)
Generate copyWith methods for Data Classes (https://github.com/xsahil03x/super_enum/issues/44)
Removed method arguments for empty union types (https://github.com/xsahil03x/super_enum/issues/52)
Fixed unhandled exception when using Generics (https://github.com/xsahil03x/super_enum/issues/22)
Added support for docComments (https://github.com/xsahil03x/super_enum/issues/28)