Bump plantuml-markdown from 3.9.7 to 3.9.8 in /config

Bumps [plantuml-markdown](https://github.com/mikitex70/plantuml-markdown) from 3.9.7 to 3.9.8.
- [Release notes](https://github.com/mikitex70/plantuml-markdown/releases)
- [Changelog](https://github.com/mikitex70/plantuml-markdown/blob/master/CHANGELOG.md)
- [Commits](mikitex70/plantuml-markdown@3.9.7...3.9.8)

---
updated-dependencies:
- dependency-name: plantuml-markdown
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

config/requirements.txt

@@ -8,5 +8,5 @@ mkdocs-print-site-plugin==2.5.0
 mkdocs-literate-nav==0.6.1
 mkdocs-jupyter==0.24.7
 mkdocs-callouts==1.13.2
-plantuml-markdown==3.9.7
+plantuml-markdown==3.9.8
 markdown-include==0.8.1