www/py-django-cacheops: Update to 6.1

• Simplify the CONFLICTS_INSTALL entry as well. This also reduces editing of the Makefile if another port need to be "repo-copied" (e.g. for Django 4.1) based on this port in the future.

Changelog:

https://github.com/Suor/django-cacheops/blob/6.1/CHANGELOG