Docker test test_fn_task_delay is failing

Apparently, the 2.24.0 version of requests released yesterday makes the Celery Docker test `test_fn_task_delay` to fail. The specific change that causes this failure is [this](https://github.com/psf/requests/pull/5492/files#diff-28e67177469c0d36b068d68d9f6043bfR662-R667) one.