Bump sphinx from 6.1.3 to 7.2.6

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 6.1.3 to 7.2.6.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v6.1.3...v7.2.6)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements/requirements-docs.txt

@@ -1,3 +1,3 @@
-Sphinx==6.1.3
+Sphinx==7.2.6
 sphinx-autobuild==2021.3.14
 sphinx-rtd-theme==1.2.2