Fix test issue caused by change in Requests library

tests/integration/models/reddit/test_subreddit.py

@@ -513,6 +513,7 @@ def patch_request(url, *args, **kwargs):
             """Patch requests to return mock data on specific url."""
             if "https://reddit-uploaded-media.s3-accelerate.amazonaws.com" in url:
                 response = requests.Response()
+                response.encoding = "utf-8"
                 response._content = mock_data.encode("utf-8")
                 response.status_code = 400
                 return response