Bump sphinx from 2.4.2 to 2.4.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 2.4.2 to 2.4.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/3.x/CHANGES)
- [Commits](sphinx-doc/sphinx@v2.4.2...v2.4.3)

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

Author: dependabot-preview[bot]

requirements-dev.txt

@@ -11,5 +11,5 @@ pyroma==2.6
 pytest-cov==2.8.1
 pytest==5.3.5
 sphinx-autodoc-typehints==1.10.3
-sphinx==2.4.2
+sphinx==2.4.3
 torch==1.4.0