Bump furo from 2023.5.20 to 2023.7.26 in /docs (#3824)

Bumps [furo](https://github.com/pradyunsg/furo) from 2023.5.20 to 2023.7.26.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2023.05.20...2023.07.26)

---
updated-dependencies:
- dependency-name: furo
  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

@@ -6,4 +6,4 @@ Sphinx==6.1.3
 docutils==0.19
 sphinxcontrib-programoutput==0.17
 sphinx_copybutton==0.5.2
-furo==2023.5.20
+furo==2023.7.26