text: Title: Bug with List of response_models taken from Serializer
  Body: ### Description
  
  When trying to use List of generated `response_model` model as response_model in route, you get in response
  
  ```json
  {
    "code": 400,
    "detail": "Validation error",
    "fields": [
      {
        "name": "response",
        "message": "Value is not a valid list"
      }
    ]
  }
  ```
  
  ### What I Did
  
  ```python
  from typing import List
  from fastapi import APIRouter, Depends
  
  from fastapi_contrib.pagination import Pagination
  from fastapi_contrib.serializers import openapi
  from fastapi_contrib.serializers.common import Serializer
  
  
  @openapi.patch
  class MySerializer(Serializer):
      ...
  
  
  router = APIRouter()
  
  
  @router.get("/", response_model=List[MySerializer.response_model])
  async def lst(pagination: Pagination = Depends()):
      return await pagination.paginate(MySerializer)
  ```
  