proper enum schema for pydantic - #651

Having a function for each of these adds a lot of bulk to the generated files, can this not go in the original definition for Enum and also be inlined into a lambda as this doesn't need type hints?

I'm fine with the suggestion. Where do you recommend to declare the validate function? We can also define it as a method in betterproto library too.

something like

def get_validate_betterproto_enum(cls):
 def validate(cls, value): 
 return cls(value)
 return validate

@Gobot1234 I'm not sure if I understood your suggestion properly actually. At least, I changed to use lambda instead.
Another option is just to define this validator as a class method for class Enum by default.

Please elaborate your suggestion again and I'd be happy to update my PR. Thanks!