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:

```python
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. https://github.com/rstudio/rsconnect-python/pull/446