* Add generic monkeypatching for `FileProxyMixin`.
This fixes `TypeError: 'type' object is not subscriptable` for
`django.core.files.File` and `django.core.files.base.ContentFile`.
* Add generic monkeypatching for `ForeignKey`.
This matches the change coming in Django 4.1.
See https://github.com/django/django/pull/15571
* run black
* create monkeypatching function for adding get_item dunder
* whoops i forgot the test
* change the name in INSTALLED_APPS to make test pass
* turn the whole thing into a proper package
* move django_stubs_ext to requirements.txt
* also install requirements.txt
* attempt to fix pre-commit
* numerous small code review fixes
* fix dependency issues
* small dependency fixes
* configure proper license file location
* add the rest of the monkeypatching
* use strict mypy
* update contributing with a note monkeypatching generics
* copy release script from parent package