Fix: Provide usage of Enums as dict keys.

src/drf_yasg/openapi.py

@@ -141,7 +141,7 @@ def _as_odict(obj, memo):
  if not isinstance(obj, dict):
  items = sorted(items)
  for attr, val in items:
- result[attr] = SwaggerDict._as_odict(val, memo)
+ result[SwaggerDict._as_odict(attr, memo)] = SwaggerDict._as_odict(val, memo)
  return result
  elif isinstance(obj, str):
  return force_real_str(obj)