Bump tox from 3.24.5 to 4.15.1

Bumps [tox](https://github.com/tox-dev/tox) from 3.24.5 to 4.15.1.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/main/docs/changelog.rst)
- [Commits](tox-dev/tox@3.24.5...4.15.1)

---
updated-dependencies:
- dependency-name: tox
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements_dev_optional.txt

@@ -12,7 +12,7 @@ types-redis
 types-setuptools
 pymongo==4.0.2
 # optional test requirements
-tox==3.24.5
+tox==4.15.1
 coverage
 flake8==4.0.1
 pytest-cov==3.0.0