create monkeypatching function for adding get_item dunder (#526)

* 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

django_stubs_ext/release.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+set -ex
+
+if [[ -z $(git status -s) ]]
+then
+  if [[ "$VIRTUAL_ENV" != ""  ]]
+  then
+    pip install --upgrade setuptools wheel twine
+    python setup.py sdist bdist_wheel
+    twine upload dist/*
+    rm -rf dist/ build/
+  else
+    echo "this script must be executed inside an active virtual env, aborting"
+  fi
+else
+  echo "git working tree is not clean, aborting"
+fi