Add code_challenge_methods_supported property to OIDC auto discovery

[gutard]

Fixes#1249

Description of the Change

Some OIDC clients require code_challenge_methods_supported to be present in auto discovery information. The PR adds this property to ConnectDiscoveryInfoView.

Checklist

• PR only contains one change (considered splitting up PR)
• unit-test added
• documentation updated
• CHANGELOG.md updated (only for user relevant changes)
• author name in AUTHORS

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (2d641f2) 97.54% compared to head (3ac4115) 97.54%.

Additional details and impacted files

@@ Coverage Diff @@## master #1367 +/- ## ======================================= Coverage 97.54% 97.54% ======================================= Files 32 32 Lines 2120 2120 ======================================= Hits 2068 2068 Misses 52 52 

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[n2ygk]

Also please "Make sure to request a review by assigning Reviewer jazzband/django-oauth-toolkit" when you are ready for review.

[gutard]

Also please "Make sure to request a review by assigning Reviewer jazzband/django-oauth-toolkit" when you are ready for review.

Yes I read this but I think I'm not allowed to. From GitHub docs:

Note: Pull request authors can't request reviews unless they are either a repository owner or collaborator with write access to the repository.

[n2ygk]

I just authorized running the tests and this is failing on tests/test_oidc_views.py:82: AssertionError. You should be able to see the links to those tests now. Please review and add the necessary changes. Thanks.

I recommend running tox locally to catch these kinds of issues before submitting a PR.
See https://django-oauth-toolkit.readthedocs.io/en/latest/contributing.html#run-the-tests

[n2ygk]

Nice job. Thanks!