Bump sphinx-toolbox from 2.17.0 to 2.18.0 (#55)

Bumps [sphinx-toolbox](https://github.com/sphinx-toolbox/sphinx-toolbox) from 2.17.0 to 2.18.0.
- [Release notes](https://github.com/sphinx-toolbox/sphinx-toolbox/releases)
- [Commits](sphinx-toolbox/sphinx-toolbox@v2.17.0...v2.18.0)

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

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements_docs.txt

@@ -1,4 +1,4 @@
 Sphinx==4.4.0
 pyansys-sphinx-theme==0.2.3
 sphinx-copybutton==0.5.0
-sphinx_toolbox==2.17.0
+sphinx_toolbox==2.18.0