False positive detection of "extra fields not permitted"

[finswimmer]

Describe the bug
When a subclass of a BaseModel sets extra=forbid all attributes of the parent class are marked as "not permitted" on initialization.

To Reproduce

from pydantic import BaseModel, Extra


class A(BaseModel):
    id: int


class B(A):
    data: List[int]
    
    class Config:
        extra = Extra.forbid


d = B(id=1, data=[1,2,3])

id is now reported as: 'id' extra fields not permitted

Expected behavior
Attributes inherited from parent class should not be reported as "not permitted"

Screenshots

Environments (please complete the following information):

• IDE: PyCharm 2020.2.1
• OS: Ubuntu 18.04, Windows 10
• Pydantic Version: 1.8.2
• Plugin version: 0.3.5

Additional context
Reporting detection of not permitted extra fields was introduced by #324 I guess inheritance wasn't considered.

Thanks a lot for this wonderful plugin 😃

[koxudaxi]

@finswimmer
I'm sorry that I forget to say the fixed version had been released 🙇