Bump furo from 2021.06.18b36 to 2023.9.10

Bumps [furo](https://github.com/pradyunsg/furo) from 2021.06.18b36 to 2023.9.10.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2021.06.18.beta36...2023.09.10)

---
updated-dependencies:
- dependency-name: furo
  dependency-type: direct:production
...

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

doc-source/requirements.txt

@@ -3,7 +3,7 @@ git+https://github.com/sphinx-toolbox/sphinx-toolbox-experimental.git
 attr-utils>=0.9.0
 default-values>=0.6.0
 extras-require>=0.5.0
-furo==2021.06.18b36
+furo==2023.9.10
 html-section>=0.3.0
 seed-intersphinx-mapping>=1.2.2
 sphinx>=3.0.3