Pytest-drf

Fixed
- Resolve incorrect typing for `ReturnsStatus` (and `ReturnsNNN` family) — see [GH12](https://github.com/theY4Kman/pytest-drf/pull/12), thanks [last-partizan](https://github.com/last-partizan)

Changed
- Remove support for Python 3.6
- Add support for Python 3.9, 3.10, and 3.11
- Add support for py.test 3.6 through 7.1

Fixed
- Resolve `typing.Protocol` `ImportError` on Python version 3.6 and 3.7

Fixed
- Resolve error when running `py.test --fixtures`

Added
- Exposed `url_for`, a compact wrapper around Django's `reverse()` to generate URLs succinctly
- Add docs/tutorial to README

Fixed
- Prefix all test methods with `test_`, so they work with standard pytest configuration (previously, tests were prefixed with `it_`, which required `python_functions` to include `it_*` in `pytest.ini`)

Changed
- Switched to [pytest-djangoapp](https://github.com/idlesign/pytest-djangoapp) (from [pytest-django](https://github.com/pytest-dev/pytest-django)) for testing