build(deps): bump furo from 2022.12.7 to 2023.8.19 in /docs

Bumps [furo](https://github.com/pradyunsg/furo) from 2022.12.7 to 2023.8.19.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2022.12.07...2023.08.19)

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

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

docs/requirements.txt

@@ -1,3 +1,3 @@
-furo==2022.12.7
+furo==2023.8.19
 myst_parser==2.0.0
 sphinx==6.1.3