Bump django-celery-beat from 1.5.0 to 1.6.0
Bump django-celery-beat from 1.5.0 to 1.6.0

Bumps [django-celery-beat](https://github.com/celery/django-celery-beat) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/celery/django-celery-beat/releases)
- [Changelog](https://github.com/celery/django-celery-beat/blob/master/Changelog)
- [Commits](https://github.com/celery/django-celery-beat/compare/1.5.0...1.6.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
gpodder/mygpo,gpodder/mygpo,gpodder/mygpo,gpodder/mygpo