Bump tox from 4.20.0 to 4.21.2 (#2496)

Bumps [tox](https://github.com/tox-dev/tox) from 4.20.0 to 4.21.2.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](tox-dev/tox@4.20.0...4.21.2)

---
updated-dependencies:
- dependency-name: tox
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements-test.txt

@@ -1,3 +1,3 @@
 coveralls==4.0.1
 pre-commit==3.8.0
-tox==4.20.0
+tox==4.21.2