Update tox to 3.24.3

[pyup-bot]

This PR updates tox from 3.24.1 to 3.24.3.

Changelog

3.24.3

Bugfixes
^^^^^^^^

- ``--parallel`` reports now show ASCII OK/FAIL/SKIP lines when full Unicode output is not available - by :user:`brettcs`
`1421 <https://github.com/tox-dev/tox/issues/1421>`_


Miscellaneous
^^^^^^^^^^^^^

- Started enforcing valid references in Sphinx docs -- :user:`webknjaz`
`2168 <https://github.com/tox-dev/tox/issues/2168>`_

3.24.2

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

Bugfixes
^^^^^^^^

- include ``LC_ALL`` to implicit list of passenv variables - by :user:`ssbarnea`
`2162 <https://github.com/tox-dev/tox/issues/2162>`_

Links

• PyPI: https://pypi.org/project/tox
• Changelog: https://pyup.io/changelogs/tox/
• Docs: http://tox.readthedocs.org

[pyup-bot]

Closing this in favor of #288