build(deps): bump sphinx from 3.5.2 to 3.5.3

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 3.5.2 to 3.5.3.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/3.x/CHANGES)
- [Commits](https://github.com/sphinx-doc/sphinx/commits)

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

Author: dependabot-preview[bot]

docs-requirements.txt

@@ -1,4 +1,4 @@
-sphinx==3.5.2
+sphinx==3.5.3
 sphinx-rtd-theme
 sphinx-autodoc-typehints[type_comments]>=1.8.0
 typing-extensions