Add a development dependency on django-stubs.
Review Request #12783 — Created Jan. 11, 2023 and submitted
django-stubsinstalls type hints for Django, helping us write more
correct code. It's not perfect, in that it works better for mypy than
pyright, but it gets us pretty far.
This is going to be required in order for some modules to import utility
type hints from this module, so that we can better type our own code.
Been using this module to verify type hints.