treewide: Support and test against Python 3.11

[fliiiix]

No description provided.

[ix5]

Nice effort, thanks for doing this.
Let's wait for the dependencies to become available for 3.11, keeping this open until then.

See also: 3.11 release schedule

[fliiiix]

It might make sense to also upgrade the Dockerfile but i could not tst that so its not included

 => ERROR [isso-builder  3/11] RUN python3 -m venv /isso  && . /isso/bin/activate  && pip3 install --no-cache-dir --upgrade pip  && pip3 install --no-cache-dir gu  0.5s

and update the docs build
https://github.com/posativ/isso/blob/master/.github/workflows/build-upload-docs.yml#L27

same issue here no idea how to test so i did not upgrade it

But I think this PR is ready to go

[ix5]

Time indeed moves fast... Totally forgot about this. Would you mind pinging me about this on Wednesday?

[fliiiix]

ping

[ix5]

Please amend the slight wording suggestion, and create a separate commit for the setup.py change.

Otherwise LGTM

[fliiiix]

I think i addressed all the feedback let me know if there is something else missing to get this merged

[ix5]

Thanks your your contribution and patience!