Model inheritance does not convert correctly

## Use Case Scenario

I've two pydantic models. Each in his own module (file). One Model, the *TUser* depends on the *TAddress*.

address_model.py
```python
class TAddress(BaseModel):
id: Optional[int]
address: Optional[constr(max_length=100, strip_whitespace=True)]
city: Optional[constr(max_length=80, strip_whitespace=True)]
postal_code: Optional[constr(max_length=15, strip_whitespace=True)]
country: Optional[constr(max_length=3)]
```

user_model.py
```python
class TUser(BaseModel):
id: UUID = None
email: Optional[EmailStr]

address: Optional[TAddress]

is_active: Optional[bool]
is_email_verified: Optional[bool]
created_at: Optional[datetime.datetime]
```

If I use the *TUser* model know for my PydanticObjectType

```python
class UserType(PydanticObjectType):
class Meta:
model = TUser
```

I get the following error message:

```
graphene_pydantic.converters.ConversionError: Don't know how to convert the Pydantic field ModelField(name='address', type=Optional[TAddress], required=False, default=None) ()
```

It seems like that there is a problem when using pydantic models from different modules that depends on each other.
What is the solution for this use case?

Any idea?