[REQ] Add overload type hints for model new

[spacether]

Is your feature request related to a problem? Please describe.

Add overload type hints for model new

Describe the solution you'd like

This will enable running mypy on models because the mixin classes will no longer collide!

Describe alternatives you've considered

Additional context

[spacether]

Note: the linked PR moves __new__ functionality into:
SomeSchema.validate or
SomeSchemaDict.__new__
SomeSchemaTuple.__new__
Where

• SomeSchemaDict is the dict output class one gets from running SomeSchema.validate for dict input
• SomeSchemaTuple is the tuple output class one gets from running SomeSchema.validate for list or tuple input

[spacether]

resolved by 3.0.0 release