chore(deps): update dependency tox to v4.21.1

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
tox (changelog)	==4.21.0 -> ==4.21.1

---

Release Notes

tox-dev/tox (tox)

### [`v4.21.1`](https://redirect.github.com/tox-dev/tox/releases/tag/4.21.1) [Compare Source](https://redirect.github.com/tox-dev/tox/compare/4.21.0...4.21.1) #### What's Changed - Fix TOML configuration errors by [@​gaborbernat](https://redirect.github.com/gaborbernat) in [https://github.com/tox-dev/tox/pull/3388](https://redirect.github.com/tox-dev/tox/pull/3388) **Full Changelog**: https://github.com/tox-dev/tox/compare/4.21.0...4.21.1

---

Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

---

• [ ] If you want to rebase/retry this PR, check this box

---

This PR was generated by Mend Renovate. View the repository job log.