build(deps): bump mkdocs-include-markdown-plugin from 3.8.0 to 3.9.1

Bumps [mkdocs-include-markdown-plugin](https://github.com/mondeja/mkdocs-include-markdown-plugin) from 3.8.0 to 3.9.1.
- [Release notes](https://github.com/mondeja/mkdocs-include-markdown-plugin/releases)
- [Commits](https://github.com/mondeja/mkdocs-include-markdown-plugin/compare/v3.8.0...v3.9.1)

---
updated-dependencies:
- dependency-name: mkdocs-include-markdown-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

docs/requirements.txt

@@ -5,5 +5,5 @@ mkdocs-macros-plugin==0.7.0
 mkdocs-material==8.5.7
 mkdocs-minify-plugin==0.6.1
 mkdocs-redirects==1.2.0
-mkdocs-include-markdown-plugin==3.8.0
+mkdocs-include-markdown-plugin==3.9.1
 mkdocs-markdownextradata-plugin==0.2.5