Bump sphinx-toolbox from 3.7.0 to 3.8.0

Bumps [sphinx-toolbox](https://github.com/sphinx-toolbox/sphinx-toolbox) from 3.7.0 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@v3.7.0...v3.8.0)

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

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