Add GitHub actions release workflow

[intgr]

Heavily based on the setup in django-stubs:

• Add GitHub actions release workflow django-stubs#1950

Benefits:

• Any maintainer can make djangorestframework-stubs releases, not just me and sobolevn.
• Hopefully this will result in more frequent releases (can avoid issues like Missing Release for latest mypy release (1.11.0) #652).
• One fewer manual step, one less thing that can go wrong. In particular, this will prevent gaffes like Version 1.9.0 overwrites DRF installation with old version #362.
• Maintainers can't inject malicious code into the PyPI release that doesn't exist in git (though we now have to trust GitHub to be not malicious).

[intgr]

@sobolevn needs to configure a PyPI trusted publisher, I'm guessing this should be:

Owner: typeddjango
Repository name: djangorestframework-stubs
Workflow name: release.yml
Environment name: release

(Related discussion in django-stubs: typeddjango/django-stubs#2114)

[intgr]

Pinging @flaeppe as the author of original django-stubs release workflow.

[sobolevn]

Working on it!

[sobolevn]

Done!

[intgr]

Now all we need is an excuse to make another release to test it 😁

[browniebroke]

I saw that there was a new django-stubs release today... Would now be a good time to make a new release for drf-stubs too? 😄

[intgr]

It worked! 🥳 https://github.com/typeddjango/djangorestframework-stubs/actions/runs/12329324930