Build(deps): Bump furo from 2022.1.2 to 2022.4.7 in /docs

Bumps [furo](https://github.com/pradyunsg/furo) from 2022.1.2 to 2022.4.7.
- [Release notes](https://github.com/pradyunsg/furo/releases)
- [Changelog](https://github.com/pradyunsg/furo/blob/main/docs/changelog.md)
- [Commits](pradyunsg/furo@2022.01.02...2022.04.07)

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

Signed-off-by: dependabot[bot] <[email protected]>

docs/requirements.txt

@@ -1,2 +1,2 @@
 sphinx==4.5.0
-furo==2022.1.2
+furo==2022.4.7