Bump sphinx-toolbox from 3.4.0 to 3.8.0

Bumps [sphinx-toolbox](https://github.com/sphinx-toolbox/sphinx-toolbox) from 3.4.0 to 3.8.0.
- [Release notes](https://github.com/sphinx-toolbox/sphinx-toolbox/releases)
- [Changelog](https://github.com/sphinx-toolbox/sphinx-toolbox/blob/master/doc-source/changelog.rst)
- [Commits](sphinx-toolbox/sphinx-toolbox@v3.4.0...v3.8.0)

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

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

Author: dependabot[bot]

requirements/local.txt

@@ -19,7 +19,7 @@ types-xmltodict
 sphinx  # https://github.com/sphinx-doc/sphinx
 sphinx-autobuild==2021.3.14 # https://github.com/GaretJax/sphinx-autobuild
 sphinx-rtd-theme==1.2.0
-sphinx_toolbox==3.4.0
+sphinx_toolbox==3.8.0
 
 # Code quality
 # ------------------------------------------------------------------------------