feat: Add credit.

Author: mike-oakley

README.md

@@ -287,6 +287,10 @@ from openapi_pydantic.v3.v3_0_3 import OpenAPI, ...
 from openapi_pydantic.v3.v3_0_3.util import PydanticSchema, construct_open_api_with_schema_class
 ```
 
+## Credits
+
+This library is based from the original implementation by Kuimono of [OpenAPI Schema Pydantic](https://github.com/kuimono/openapi-schema-pydantic) which is no longer actively maintained.
+
 ## License
 
 [MIT License](https://github.com/mike-oakley/openapi-pydantic/blob/main/LICENSE)