pydantic v2.0 breaking prototypes

[isabelizimm]

Pydantic's V2.0 will break prototype creation in vetiver.

To reproduce error:

1. Update to Pydantic V2.0 (compatible FastAPI release is not out yet, you must pip install --pre --upgrade fastapi pydantic).
2. Run:

from vetiver import mock, VetiverModel, VetiverAPI

X, y = mock.get_mock_data()
model = mock.get_mock_model().fit(X, y)
v = VetiverModel(
    model=model,
    prototype_data=X,
    model_name="my_model",
    versioned=None,
    description="A regression model for testing purposes",
)

Output:

PydanticUserError: A non-annotated attribute was detected: `B = {0: 22, ... 99: 84}`. 
All model fields require a type annotation; if `B` is not meant to be a field, you may 
be able to resolve this error by annotating it as a `ClassVar` or updating
`model_config['ignored_types']`.

For further information visit https://errors.pydantic.dev/2.0/u/model-field-missing-annotation

This is happening at the dynamic creation of prototypes using pydantic.create_model()

[toph-allen]

This issue caused some CI failures for rsconnect-python. We fixed them adding pydantic<2.0.0 to the requirements file that's used. posit-dev/rsconnect-python#446