devel/py-dj42-django-rq: Update to 2.10.1

• Remove no longer required patch since 7a59772ca5ae.

While I'm here:

• Fix the test suite as the "django-admin" script is shipped nowadays without the ".py" extension.
• Reduce the set of required dependencies for it as well.

Changelog since 2.9.0:

https://github.com/rq/django-rq/blob/v2.10.1/CHANGELOG.md