Make coreapi & markdown requirements optional

[intgr]

I have made things!

The coreapi and markdown dependencies in Django REST Framework have been optional for a long time, but installing a stubs package pulls them in regardless. I have moved these to "extras" dependencies. I tested this in my project and it causes no additional mypy inspections.

• coreapi was deprecated from DRF in 2019.
• Markdown support has always been optional.

Related issues

• Fixes Can 'coreapi' dependency be dropped? #145

[sobolevn]

Awesome, thanks!

[sobolevn]

Please, fix black 🙂

[intgr]

Fixed Black.

Oh, also, should requirements.txt be updated to install these extras?

-e .[compatible-mypy,coreapi,markdown]

[sobolevn]

In development, yes, we want everything. Let's make -e .[all] for this case.

[intgr]

This is now causing warnings with Python 3.11.

1. I'm importing rest_framework in my code
2. REST framework has an optional import of coreapi -- if coreapi is missing, there wouldn't be a problem
3. djangorestframework-stubs requires installing coreapi
4. coreapi imports Python's cgi module
5. Python displays DeprecationWarning

Sorry to sound grumpy, but it's demotivating to work TypedDjango knowing it will take many months before there's a release and I'm able to take advantage of the changes. I do understand that TypedDjango maintainers are doing this in a volunteer capacity.

I was hoping that #228 would result in more frequent releases, but that has not happened.