* Test dependabot for Dockerfiles.
* Also for github actions
* Update dependabot.yml
* Fix urls.py for new versions of Django
* Fix urls.py for postorius.
* Bump dependency on Postgresql.
* Bump dependency on Django
* Add dependency on tzdata.
* Remove the secret key.
* Use the latest tag for postorius.
* Use the latest django-mailman3 that supports Python 3.
* Use minimum version on Django-mailman3.
* Fix import errors.