Bump tox from 3.23.1 to 3.24.1 (#800)

Bumps [tox](https://github.com/tox-dev/tox) from 3.23.1 to 3.24.1.
- [Release notes](https://github.com/tox-dev/tox/releases)
- [Changelog](https://github.com/tox-dev/tox/blob/master/docs/changelog.rst)
- [Commits](tox-dev/tox@3.23.1...3.24.1)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements_dev_optional.txt

@@ -11,7 +11,7 @@ redis==3.5.3
 types-redis
 pymongo==3.11.4
 # optional test requirements
-tox==3.23.1
+tox==3.24.1
 coverage
 flake8==3.9.2
 pytest-cov==2.12.1