feat: Support Django 4.2

[simkimsia]

Description

In tox.ini:

• Replace whitelist_externals with allowlist_externals because whitelist_externals is deprecated
• Added isolated_build = True
• Remove install_command where it calls tox_install.sh
• Drop tool.poetry.dev-dependencies and switch to using tool.poetry.extras in order for tox to detect them

In ci.yml

• Because now use tool.poetry.extras so when call poetry install need to incldue —extras ‘test’ as argument

The last 2 points about dropping dev-dependencies and using extras are from https://github.com/orgs/python-poetry/discussions/4307#discussioncomment-1041658

Fixes #212, #214, #215, #216, #218

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have added an appropriate CHANGELOG entry

[simkimsia]

This is the cleaned up version of PR #213

I hope this can be accepted despite completely changing the way the tox and poetry coexists from the previous way.

If this is accepted, my next PR would be to remove tox_install.sh completely

Thank you.

[simkimsia]

@thibaudcolas or @bcdickinson can help to review this PR? Thank you

Update

Ignore this since I'm closing this in favor of #220

[simkimsia]

#221 is a better issue for this and
#220 is a less invasive, more targeted PR than this