Bump tox from 4.18.1 to 4.20.0 in /test

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>

test/requirements.txt

@@ -2,5 +2,5 @@ pyyaml == 6.0.2
 pytest == 8.3.3
 pytest-xdist == 3.6.1
 pytest-testinfra == 10.1.1
-tox == 4.18.1
+tox == 4.20.0
 pytest-clarity == 1.0.1