Bump tox from 4.18.1 to 4.20.0 (#11562)

Bumps [tox](https://github.com/tox-dev/tox) from 4.18.1 to 4.20.0.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](https://github.com/tox-dev/tox/compare/4.18.1...4.20.0)

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

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

tests/requirements.txt

@@ -7,6 +7,6 @@ molecule==24.9.0
 molecule-plugins[vagrant]==23.5.3
 pytest-testinfra==10.1.1
 python-vagrant==1.0.0
-tox==4.18.1
+tox==4.20.0
 tzdata==2024.1
 yamllint==1.35.1