Extend test matrix up to 3.12

[foarsitter]

In the same vein as #481, this PR updates the test matrix & classifiers up to the most recent 3.12.

Checklist

General Contributing

• Have you read the Code of Conduct and signed the CLA?

Is This a Code Change?

• Non-code related change (markdown/git settings etc)
• SDK Code Change
• Example/Test Code Change

Validation

• Does tox pass?
• Do the tests pass?

[CLAassistant]

All committers have signed the CLA.

[greg-db]

Thanks for putting this together! I'll ask the team to review this.

[hugovk]

Does this fail on 3.12 with #483?

[sarahboyce]

dropbox-sdk-python/setup.py

Line 36 in f40e73f

'pytest-runner == 5.2.0',

I think something like 'setuptools; python_version>="3.12"' should be added to the setup_requires list.
Without this I can't create a virtual env for this library on Python 3.12

See: https://docs.python.org/3/whatsnew/3.12.html

• gh-95299: Do not pre-install setuptools in virtual environments created with venv. This means that distutils, setuptools, pkg_resources, and easy_install will no longer available by default; to access these run pip install setuptools in the activated virtual environment.

[foarsitter]

@hugovk It did not fail on 3.12 for the CI: https://github.com/foarsitter/dropbox-sdk-python/actions/runs/6707504248

[sarahboyce]

@hugovk It did not fail on 3.12 for the CI: https://github.com/foarsitter/dropbox-sdk-python/actions/runs/6707504248

@foarsitter this is because requirements.txt also includes some requirements for development including sphinx which installs setuptools. Ref raw logs of the action:

2023-10-31T13:53:47.3735410Z Collecting setuptools (from babel>=2.9->sphinx->-r requirements.txt (line 9))

I think the packages in the requirements.txt under # Other dependencies for development should be in their own requirements file and not installed in the CI (sphinx for example is explicitly installed in the docs ci step anyway).

If you remove sphinx from requirements.txt, I think that the Python 3.12 ci will fail.
I believe #484 (comment) is needed. I can't activate a virtual environment here on Python 3.12 without this change.

[foarsitter]

@sarahboyce do you think it is sufficient to not pin setuptools and let pip decide? Thanks for pointing out that sphinx was installing setuptools in this case.

I added an issue to move to pyproject.toml: #487

[sarahboyce]

@foarsitter this is great! 🌟
Good idea to raise a separate issue around the setup, this PR achieves what we need 👍