Find a replacement for drf-yasg that's compatible with Python 3.10

The demo project is [failing](https://app.circleci.com/pipelines/github/jacebrowning/template-django-demo/121/workflows/90ef50ce-2b9c-48de-b9e3-3a0f3c5e4425/jobs/241) on CircleCI:

```
File "/home/circleci/demo_project/.venv/lib/python3.10/site-packages/drf_yasg/__init__.py", line 2, in
from pkg_resources import DistributionNotFound, get_distribution
ModuleNotFoundError: No module named 'pkg_resources'
```

Start with the linked CircleCI job to confirm the Python 3.10 failure, then inspect how the demo project depends on drf-yasg. Identify a compatible replacement and verify that the demo project passes its CircleCI build with the replacement in place.

Written by the indexing model from the issue text.