Fix pylint by ignoring private access

Author: ericholscher

readthedocs/proxito/middleware.py

@@ -186,6 +186,7 @@ def add_user_headers(self, request, response):
         if hasattr(request, 'domain'):
             # Use a private method to get this
             # TODO: In Django 3.2 this has been upgraded to a top-level method
+            # pylint: disable=protected-access
             response_headers = [header.lower() for header in response._headers.keys()]
             log.info('Response headers=%s', response_headers)
             for http_header in request.domain.http_headers.all():