try to fix CI by avoiding py312, take 2

[loriab]

Attempt to take the easy way out of #274 .

~Sorry, I forgot GH edits would make branches on upstream, which isn't set up to avoid doubling the lanes with push/pull_request.~

• [x] edited GHA frontmatter so that WIP branches on upstream don't get CI tested until they become PRs
• [x] from options on https://github.com/evaleev/libint/issues/274#issuecomment-1808505188 , this PR skips testing pylibint2 on Mac in the Build/Repo job and instead relies on testing it twice in the Build/Export job, where python version is controlled by conda.

[loriab]

ADDED: ignore, unless you want to trace failed attempts.

nope, macos-12 still gives py312. macos-11 was working for 22 min to solve brew install (maybe could go back from python@3.11 -> python3 and it would solve? brew swich has been removed. brew reinstall python@3.11 ends with the below. homebrew rather seems to have gotten out of the flexible solve business, so it may not be of much use here to clobber system python.

Possibly one could use setup-python from GHA marketplace and then pip install numpy to get wheels. Or conda.

==> Pouring python@3.11--3.11.6.monterey.bottle.tar.gz
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink bin/2to3
Target /usr/local/bin/2to3
already exists. You may want to remove it:
  rm '/usr/local/bin/2to3'

To force the link and overwrite all conflicting files:
  brew link --overwrite python@3.11

To list all files that would be deleted:
  brew link --overwrite --dry-run python@3.11

Possible conflicting files are:
/usr/local/bin/2to3 -> /Library/Frameworks/Python.framework/Versions/3.12/bin/2to3
/usr/local/bin/2to3-3.11 -> /Library/Frameworks/Python.framework/Versions/3.11/bin/2to3-3.11
/usr/local/bin/idle3 -> /Library/Frameworks/Python.framework/Versions/3.12/bin/idle3
/usr/local/bin/idle3.11 -> /Library/Frameworks/Python.framework/Versions/3.11/bin/idle3.11
/usr/local/bin/pydoc3 -> /Library/Frameworks/Python.framework/Versions/3.12/bin/pydoc3
/usr/local/bin/pydoc3.11 -> /Library/Frameworks/Python.framework/Versions/3.11/bin/pydoc3.11
/usr/local/bin/python3 -> /Library/Frameworks/Python.framework/Versions/3.12/bin/python3
/usr/local/bin/python3-config -> /Library/Frameworks/Python.framework/Versions/3.12/bin/python3-config
/usr/local/bin/python3.11 -> /Library/Frameworks/Python.framework/Versions/3.11/bin/python3.11
/usr/local/bin/python3.11-config -> /Library/Frameworks/Python.framework/Versions/3.11/bin/python3.11-config
==> /usr/local/Cellar/python@3.11/3.11.6/bin/python3.11 -Im ensurepip
==> /usr/local/Cellar/python@3.11/3.11.6/bin/python3.11 -Im pip install -v --no-
==> Caveats
Python has been installed as
  /usr/local/bin/python3

Unversioned symlinks `python`, `python-config`, `pip` etc. pointing to
`python3`, `python3-config`, `pip3` etc., respectively, have been installed into
  /usr/local/opt/python@3.11/libexec/bin

You can install Python packages with
  pip3 install <package>
They will install into the site-package directory
  /usr/local/lib/python3.11/site-packages

tkinter is no longer included with this formula, but it is available separately:
  brew install python-tk@3.11

gdbm (`dbm.gnu`) is no longer included in this formula, but it is available separately:
  brew install python-gdbm@3.11
`dbm.ndbm` changed database backends in Homebrew Python 3.11.
If you need to read a database from a previous Homebrew Python created via `dbm.ndbm`,
you'll need to read your database using the older version of Homebrew Python and convert to another format.
`dbm` still defaults to `dbm.gnu` when it is installed.

For more information about Homebrew and Python, see: https://docs.brew.sh/Homebrew-and-Python
==> Summary
🍺  /usr/local/Cellar/python@3.11/3.11.6: 3,284 files, 61.8MB
Error: Process completed with exit code 1.