django-allauth v64 migration

[dpgraham4401]

Description

This PR migrates dj-rest-auth to the newest major version of django-allauth. It, unfortunately, forces `dj-rest-auth to increment the major version since it follows django-allauth support for django, and drops support for django < 4.2.

Related tickets

closes #646

see also #639

Notes

• fixes a format error that was causing CI to fail from refresh token is not shown in the swagger #247
• I removed a couple test that were dependent on objects that are no longer exported from django-allauth (see a89f6df)
• Since these changes add support for django 5.0, it replaces django.utils.timezone usage (which was deprecated in django 4.1 and removed in django 5) with the standard library datetime module (see django deprecateion notice here)
• I converted the requirement.pip files to requirements.txt file which is newer widely used name. I did this for convenience for my local development environment, but can be reverted. The changes also include changes to the docs.
• adjust the CI to reflect the removed and added support for django version.

[Downchuck]

@iMerica Checking in on the status of this PR?

[dan-blanchard]

• Since these changes add support for django 5.0, it replaces django.utils.timezone usage (which was deprecated in django 4.1 and removed in django 5) with the standard library datetime module (see django deprecateion notice here)

django.utils.timezone was not removed entirely and django.utils.timezone.now is still the recommended way to get tz-aware datetimes in the Django docs. What was removed were a few aliases they had before and supports for pytz. The changes you have related to that are unnecessary, and datetime.utcnow() is actually deprecated and not something that you should be replacing it with (because ironically utcnow() does not get you are tz-aware date).

[iMerica]

Can you address merge conflicts?

[dpgraham4401]

@iMerica yes, I can address the merge conflicts.

[dpgraham4401]

@iMerica this is ready for review

[iMerica]

Linter:

dj_rest_auth/tests/test_api.py:531:5: E303 too many blank lines (2)

[dpgraham4401]

@dan-blanchard I've make the timezone import changes per your docs, thanks for the pointer!

@iMerica I've made a few changes to the flake8 configs that align running the linter locally and in the CI.

1. update the flake8 version in the various configs (requirements.txt, setup.py). I could not even run flake8 v3 with pyhton 3.12 locally.
2. Make sure the same version is used in GitHub actions as what's in the requirements.txt file.
3. I took the liberty of inlining the additional .flake8 config file into setup.cfg, this simplifies the call to lint through just the flake8 CLI and in the tox config and CI definition. However, I can undo this if there was a good reason for these configs to reside in .flake8
4. Add the socialacount optional dependency group of django-allauth in the test/requirements.txt file so the tests pass.
5. Add Python 3.12 to the tox GitHub Actions config