Bump sphinx from 5.3.0 to 7.0.0 in /docs

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 5.3.0 to 7.0.0.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES)
- [Commits](sphinx-doc/sphinx@v5.3.0...v7.0.0)

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

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

docs/requirements.txt

@@ -1,5 +1,5 @@
 furo==2023.3.27
-sphinx==5.3.0
+sphinx==7.0.0
 sphinx-click==4.4.0
 sphinx-copybutton==0.5.2
 myst_nb==0.17.2