Set min supported Django version in pyproject.toml, pt. 2
Set min supported Django version in pyproject.toml, pt. 2

The previous version only allowed Django 2 because that's how `^` works
(duh). Need to use `>=` instead.

Amends 1ae005c7be57281318fb5c2da226d63bb6cb9431

wylee/django-local-settings