Bump tox from 3.23.0 to 3.23.1

Bumps [tox](https://github.com/tox-dev/tox) from 3.23.0 to 3.23.1.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/master/docs/changelog.rst)
- [Commits](tox-dev/tox@3.23.0...3.23.1)

Signed-off-by: dependabot[bot] <support@github.com>

requirements-dev.txt

@@ -7,7 +7,7 @@ pydocstyle==6.0.0
 docformatter==1.4
 coverage==5.5
 autoflake==1.4
-tox==3.23.0
+tox==3.23.1
 pur==5.4.0
 wheel==0.36.2
 setuptools==56.0.0