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
...

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