Update tox to 4.20.0

[pyup-bot]

This PR updates tox from 3.24.5 to 4.20.0.

Changelog

3.28.0

--------------------

Features
^^^^^^^^

- Support provision of tox 4 with the ``min_version`` option - by :user:`hroncok`
`2661 <https://github.com/tox-dev/tox/issues/2661>`_

3.27.1

--------------------

Bugfixes
^^^^^^^^

- Replaced deprecated ``license_file`` key with ``license_files`` in ``setup.cfg`` -- by :user:`mgorny`.
`2521 <https://github.com/tox-dev/tox/issues/2521>`_
- Add env cleanup to envreport - fix PYTHONPATH leak into "envreport" -- by :user:`f3flight`.
`2528 <https://github.com/tox-dev/tox/issues/2528>`_

3.27.0

--------------------

Bugfixes
^^^^^^^^

- Dropped ``--build-option`` in isolated builds, an alternative fix for the ``SetuptoolsDeprecationWarning`` about using ``--global-option`` -- by :user:`adamchainz`
`2497 <https://github.com/tox-dev/tox/issues/2497>`_
- Remove read-only files in ``ensure_empty_dir``.
`2498 <https://github.com/tox-dev/tox/issues/2498>`_
- Multiple tox instances no longer clobber the ``.tox`` directory when
``provision_tox_env`` is used. - by :user:`masenf`
`2515 <https://github.com/tox-dev/tox/issues/2515>`_


Documentation
^^^^^^^^^^^^^

- Clarify that ``install_command`` only takes one command - by :user:`jugmac00`
`2433 <https://github.com/tox-dev/tox/issues/2433>`_
- Documented problems with plugin and provision env - by :user:`ziima`.
`2469 <https://github.com/tox-dev/tox/issues/2469>`_

3.26.0

--------------------

Bugfixes
^^^^^^^^

- Fix fallback to ``python`` environment when ``isolated_build = true`` is set -- by :user:`Unrud`
`2474 <https://github.com/tox-dev/tox/issues/2474>`_
- Fixed ``SetuptoolsDeprecationWarning`` about using ``--global-option`` -- by :user:`adamchainz`
`2478 <https://github.com/tox-dev/tox/issues/2478>`_


Features
^^^^^^^^

- Use ``tomllib`` on Python 3.11 or later and ``tomli`` instead of ``toml`` library on lower versions - by :user:`hroncok`.
`2463 <https://github.com/tox-dev/tox/issues/2463>`_

3.25.1

--------------------

Bugfixes
^^^^^^^^

- ``sitepackages = true`` will add user's site-package to the python path on Windows as expected -- by :user:`niander`
`2402 <https://github.com/tox-dev/tox/issues/2402>`_
- Avoid importing ``pipes`` on Python 3.3+ to avoid ``DeprecationWarning`` on Python 3.11 -- by :user:`adamchainz`
`2417 <https://github.com/tox-dev/tox/issues/2417>`_
- Fix ``isolated_build`` when the build process produces stderr at exit.
`2449 <https://github.com/tox-dev/tox/issues/2449>`_


Documentation
^^^^^^^^^^^^^

- Explain advantages of ``PIP_CONSTRAINT`` environment variable over ``--constraint`` argument.
`2423 <https://github.com/tox-dev/tox/issues/2423>`_

3.25.0

--------------------

Bugfixes
^^^^^^^^

- Fixed failing isolated_build because setuptools warning was captured
in ``build_requires``. -- by :user:`zariiii9003`
`2332 <https://github.com/tox-dev/tox/issues/2332>`_
- Avoid potential 30s delay caused by socket.getfqdn(). -- by :user:`ssbarnea`
`2375 <https://github.com/tox-dev/tox/issues/2375>`_


Features
^^^^^^^^

- Ignore missing commands if they are prefixed by ``-``
-- by :user:`cdown`.
`2315 <https://github.com/tox-dev/tox/issues/2315>`_
- Add default environment variables (such as http_proxy) regardless of their case to passenv on UNIX -- by :user:`poggenhans`.
`2372 <https://github.com/tox-dev/tox/issues/2372>`_
- On Windows ``PROGRAMFILES``, ``PROGRAMFILES(X86)``, and ``PROGRAMDATA`` environment variables are now passed through, unmasking system values necessary to locate resources such as a C compiler.
`2382 <https://github.com/tox-dev/tox/issues/2382>`_


Documentation
^^^^^^^^^^^^^

- Deleted the tox mailing list -- by :user:`jugmac00`
`2364 <https://github.com/tox-dev/tox/issues/2364>`_

Links

• PyPI: https://pypi.org/project/tox
• Changelog: https://data.safetycli.com/changelogs/tox/

[pyup-bot]

Closing this in favor of #445