docs: using openapi generator

Author: gierschv

README.md

@@ -11,8 +11,6 @@ You can find the API reference including code samples and our OpenAPI Specificat
 
 To request some API credentials, please visit [https://flat.io/developers](https://flat.io/developers).
 
-This Python package is automatically generated by the [Swagger Codegen](https://github.com/swagger-api/swagger-codegen) project.
-
 ## Requirements.
 
 Python 2.7 and 3.4+