chore(deps): update dependency tox to v4

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
tox	==3.20.1 -> ==4.15.0
tox	==3.26.0 -> ==4.15.0

---

Configuration

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

🚦 Automerge: Enabled.

♻ Rebasing: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

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

---

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

---

This PR has been generated by Mend Renovate. View repository job log here.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 33.67%. Comparing base (ad09368) to head (d8195ab).

❗ Current head d8195ab differs from pull request most recent head 33c6bc2. Consider uploading reports for the commit 33c6bc2 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #706   +/-   ##
=======================================
  Coverage   33.67%   33.67%           
=======================================
  Files           5        5           
  Lines         677      677           
=======================================
  Hits          228      228           
  Misses        449      449           

Flag	Coverage Δ
unittests	33.67% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.