Removes default_app_config for Django Deprecation Warning

[pcarn]

Description of the Change

Fixes Django Deprecation Warning
/usr/local/lib/python3.9/site-packages/django/apps/registry.py:91: RemovedInDjango41Warning: 'oauth2_provider' defines default_app_config = 'oauth2_provider.apps.DOTConfig'. Django now detects this configuration automatically. You can remove default_app_config.

Checklist

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

Confirmed that tox passed locally

[auvipy]

something like https://github.com/celery/django-celery-beat/blob/master/django_celery_beat/__init__.py#L34 would be better, https://github.com/celery/django-celery-beat/blob/master/django_celery_beat/__init__.py#L9

[pcarn]

cd44923
8bd48c8

[codecov]

Codecov Report

Merging #1035 (a6fcd37) into master (401d856) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1035   +/-   ##
=======================================
  Coverage   96.62%   96.62%           
=======================================
  Files          31       31           
  Lines        1746     1748    +2     
=======================================
+ Hits         1687     1689    +2     
  Misses         59       59           

Impacted Files	Coverage Δ
oauth2_provider/__init__.py	100.00% <100.00%> (ø)

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[auvipy]

not sure 3.6 is failing

[pcarn]

It passes locally for me:

_______________________________________________________ summary ________________________________________________________
  py36-dj32: commands succeeded
  py36-dj31: commands succeeded
  py36-dj22: commands succeeded
  congratulations :)

But if I don't have django installed in the environment where tox is being run, it fails with the same error.

[pcarn]

@auvipy I think the fix would be to install django before running tox, which I added in d49e52a.

Let me know if that's fine.

[pcarn]

@auvipy Can you run the build for that and see if it works?

[auvipy]

started. was in vacation

[auvipy]

can you check the py3.8 failure please?

[pcarn]

3.8 is failing because it's the only one that runs tox -e docs.
When I try locally, the same failure happens on the master branch.

I found it's because m2r has mistune unpinned, and they released breaking changes.

I pinned it to <2, and it works locally now.
pcarn@a6fcd37