CI-fixes PR #2: Use Python 3.11,12,13 & document pytest venv setup

[bernhardkaindl]

@chunjiez, The documentation to run pytest is in the commit to CONTRIBUTING.md:

Development setup

Create a virtual environment with the test dependencies

python -m venv .venv
. .venv/bin/activate
pip install pip-tools==7.3.0
pip-compile --extra=test,mypy,pyright,pytype,tox -o - pyproject.toml | pip install -r /dev/stdin

Commits in this PR:

• Use Python 3.11, 3.12 and 3.13 for GitHub CI and for tox (can be used to run CI locally)
• Update CONTRIBUTING.md: Add doc on how to set up a venv for pytest, add alternative using pipx
• tests/test_logger.py: Use pyfakefs: don't create a file in the host
• .github/workflows/main.yml: Cleanup checks using Python 2.7/3.8 (Have not run since November 2024)

[coveralls]

Pull Request Test Coverage Report for Build 11862180821

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• 12 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.009%) to 83.661%

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Files with Coverage Reduction	New Missed Lines	%
xcp/accessor.py	1	89.1%
xcp/xmlunwrap.py	2	92.31%
xcp/cpiofile.py	3	75.26%
xcp/compat.py	6	78.57%

Totals
Change from base Build 9109272969:	-0.009%
Covered Lines:	2806
Relevant Lines:	3354

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💛 - Coveralls

[bernhardkaindl]

Merged with #149