Add support for Python 3.12

[kristapsk]

Currently tests on Python 3.12 are failing.

https://github.com/roshii/joinmarket-clientserver/actions/runs/6681650313/job/18155992988

https://github.com/roshii/joinmarket-clientserver/actions/runs/6681650313/job/18155993117

[kristapsk]

See also #1587.

[svpi11]

Would be great to make the Qt portable to python 3.12 :)

[kristapsk]

Qt GUI should be ported to Qt 6 first, there are problems with it since Python 3.10. #1376

[kristapsk]

Trying to get install.sh --develop -p python3.12 --without-qt working on Ubuntu 22.04 under WSL.

Currently stuck with:

$ ./install.sh --develop -p python3.12 --without-qt
Directory jmvenv exists.  Remove and recreate? (y/N) y
Error: Command '['/home/user/git/joinmarket-clientserver/jmvenv/bin/python3.12', '-m', 'ensurepip', '--upgrade', '--default-pip']' returned non-zero exit status 1.
Joinmarket Python virtual environment could not be setup. Exiting.

ensurepip is called by python3.12 -m venv /home/user/git/joinmarket-clientserver/jmvenv.

Tried https://ubuntuhandbook.org/index.php/2023/10/fix-broken-pip-python-312-ubuntu/, but only installing pip with get-pip.py works for me, but that doesn't fix anything.

Are others experiencing the same with Python 3.12? Pretty sure it's not related to running Ubuntu under WSL.

[kristapsk]

This currently seems to be the biggest issue regarding dependencies.

[roshii]

Are others experiencing the same with Python 3.12? Pretty sure it's not related to running Ubuntu under WSL.

I did manage install joinmarket with Python 12 on Alpine Linux 3.18 - tested directory node script which seem to work as expected.
I also tested install.sh --develop -without-qt with Python 3.12.3 installed via pyenv on Arch Linux: no issue encountered while installing.

Tests suite is now passing successfully. I shall create PR to reflect this: we are Python 12 compatible !