build(deps): bump sphinx from 7.1.2 to 7.2.6 in /docs (#3133)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 7.1.2 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](https://github.com/sphinx-doc/sphinx/compare/v7.1.2...v7.2.6

)

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

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

docs/requirements.txt

-Sphinx==7.1.2
+Sphinx==7.2.6
 sphinx-rtd-theme==2.0.0