Added django 4 to CI

[WisdomPill]

Fixes #579

Added support for django 4.0

[codecov]

Codecov Report

Merging #580 (cb26c50) into master (218e47c) will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #580   +/-   ##
======================================
  Coverage    57.8%   57.8%           
======================================
  Files          39      39           
  Lines        2497    2497           
  Branches       73      73           
======================================
  Hits         1441    1441           
  Misses       1041    1041           
  Partials       15      15           

Flag	Coverage Δ
mypy	33.9% <ø> (ø)
tests	83.3% <ø> (ø)

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[hartwork]

Hi @WisdomPill , four things I noticed:

• Adding support for Django 4 seems uncontroversial, dropping 2.2 prior to EOL could be considered controversial by some; I'd split those in two pull requests personally
• The current title of the pull request does not mention dropping Django 2.2; my vote for adding that
• Django 3.1 is EOL even before Django 2.2 (see image below) but it is not being dropped; why not?
• Dropping of Django 2.2 seems to be incomplete, e.g. I still see a line 2.2: dj22 in setup.cfg, maybe more.

Just my 2 cents.

[hartwork]

• Dropping of Django 2.2 seems to be incomplete, e.g. I still see a line 2.2: dj22 in setup.cfg, maybe more.

PS: @WisdomPill there is indeed one more: README.rst still says Django 2.2+ after this PR in status quo.

[WisdomPill]

my mistake, dropping 2.2 is a mistake the docs were saying that support for django 1.11 has dropped in april 2020

[WisdomPill]

thanks @hartwork !