Fix base python conflict (tox-dev#77)

Fix CI for new UV (tox-dev#74)

Python preference (tox-dev#70)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Bernát Gábor <bgabor8@bloomberg.net>

fix(venv): respect base_python passed as absolute path (tox-dev#69)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Fix failure when running within a UV venv activated shell (tox-dev#66)

[pre-commit.ci] pre-commit autoupdate (tox-dev#58)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Fix interpreter (tox-dev#53)

Fix environment check (tox-dev#52)

Add PyPy support (tox-dev#51)

Pass sys.executable to `uv venv` if it is the same version (tox-dev#40)

* Pass sys.executable to `uv venv` if it is the same version

Support the case when pythonX.Y is not in the search path, but
it corresponds to the currently running Python interpreter.

This may happen if e.g. Tox is installed (along with tox-uv) in
a virtual environment that has been created with a Python interpreter
coming from a non-standard location, and then `tox` is invoked
directly from the virtual environment's `bin/` directory:

    [roam@straylight ~]$ mkdir ~/not-in-path

    [roam@straylight ~]$ uv venv -p /opt/some-vendor/python3/bin/python3 ~/not-in-path/venv
    Using Python 3.8.17 interpreter at: /opt/some-vendor/python3/bin/python3
    Creating virtualenv at: /home/roam/not-in-path/venv
    Activate with: source /home/roam/not-in-path/venv/bin/activate

    [roam@straylight ~]$ (set -e; . ~/not-in-path/venv/bin/activate; uv pip install tox tox-uv)
    ...snip...

    [roam@straylight ~]$ printf -- '%s\n' '[testenv]' 'package=skip' 'commands=python3 -c "print()"' > ~/not-in-path/tox.ini

    [roam@straylight ~]$ ~/not-in-path/venv/bin/tox -c ~/not-in-path/tox.ini
    py: venv /home/roam/not-in-path> venv/bin/uv venv -p 3.8 /home/roam/not-in-path/.tox/py/.venv
      × No Python 3.8 in `PATH`. Is Python 3.8 installed?
    py: exit 1 (0.01 seconds) /home/roam/not-in-path> venv/bin/uv venv -p 3.8 /home/roam/not-in-path/.tox/py/.venv pid=1059253
      py: FAIL code 1 (0.02 seconds)
      evaluation failed :( (0.11 seconds)

    [roam@straylight ~]$

* Let Ruff know that we try to use subprocess responsibly

* Tox is certainly installed during the test suite run