Bump tox from 3.24.3 to 3.24.4 (#833)

Bumps [tox](https://github.com/tox-dev/tox) from 3.24.3 to 3.24.4.
- [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@3.24.3...3.24.4)

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

Signed-off-by: dependabot[bot] <support@github.com>

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

Author: dependabot[bot]

requirements_dev_optional.txt

@@ -12,7 +12,7 @@ types-redis
 types-setuptools
 pymongo==3.12.0
 # optional test requirements
-tox==3.24.3
+tox==3.24.4
 coverage
 flake8==3.9.2
 pytest-cov==2.12.1