build(deps): bump mkdocs-include-markdown-plugin from 6.0.7 to 6.2.1

Bumps [mkdocs-include-markdown-plugin](https://github.com/mondeja/mkdocs-include-markdown-plugin) from 6.0.7 to 6.2.1.
- [Release notes](https://github.com/mondeja/mkdocs-include-markdown-plugin/releases)
- [Commits](mondeja/mkdocs-include-markdown-plugin@v6.0.7...v6.2.1)

---
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>

requirements.txt

@@ -26,4 +26,4 @@ asciinema==2.4.0
 
 # https://github.com/mondeja/mkdocs-include-markdown-plugin (ASL)
 # Possible alternative: https://github.com/cmacmackin/markdown-include (GPL)
-mkdocs-include-markdown-plugin==6.0.7
+mkdocs-include-markdown-plugin==6.2.1