convert header value to str in case its an int or other simple type.

Author: tedchamb

azure-devops/azure/devops/client.py

@@ -91,7 +91,7 @@ def _send(self, http_method, location_id, version, route_values=None,
  'Accept': accept_media_type + ';api-version=' + negotiated_version}
  if additional_headers is not None:
  for key in additional_headers:
- headers[key] = additional_headers[key]
+ headers[key] = str(additional_headers[key])
  if self.config.additional_headers is not None:
  for key in self.config.additional_headers:
  headers[key] = self.config.additional_headers[key]