chore(deps-dev): bump sphinx from 2.4.3 to 2.4.4 (#272)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 2.4.3 to 2.4.4.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/3.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v2.4.3...v2.4.4)

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

Author: overcat