Run CI tests weekly.
Run CI tests weekly.

This helps identify issues with the library as
django and other dependencies release new versions.

django-debug-toolbar/django-debug-toolbar,spookylukey/django-debug-toolbar,spookylukey/django-debug-toolbar,jazzband/django-debug-toolbar,jazzband/django-debug-toolbar,spookylukey/django-debug-toolbar,django-debug-toolbar/django-debug-toolbar,jazzband/django-debug-toolbar,django-debug-toolbar/django-debug-toolbar,tim-schilling/django-debug-toolbar,tim-schilling/django-debug-toolbar,tim-schilling/django-debug-toolbar