chore(python): bump sphinx-toolbox from 3.7.0 to 3.8.0 in /py-polars

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:production
  update-type: version-update:semver-minor
...

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

py-polars/docs/requirements-docs.txt

@@ -14,6 +14,6 @@ sphinx-copybutton==0.5.2
 sphinx-design==0.6.0
 sphinx-favicon==1.0.1
 sphinx-reredirects==0.1.4
-sphinx-toolbox==3.7.0
+sphinx-toolbox==3.8.0
 
 livereload==2.7.0