[Bug 🐞] object has no attribute 'model_fields'

After redis-om `>=0.3.4` I get.

I am still on pydantic v1

```py
e-packages/aredis_om/model/model.py", line
          1465, in __init__
              missing_fields =
          __pydantic_self__.model_fields.keys() -
          data.keys() - {"pk"}
          AttributeError: 'Email' object has no
          attribute 'model_fields'
```