Bump mkdocs-d2-plugin from 1.5.0 to 1.6.0

Bumps [mkdocs-d2-plugin](https://github.com/landmaj/mkdocs-d2-plugin) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/landmaj/mkdocs-d2-plugin/releases)
- [Changelog](https://github.com/landmaj/mkdocs-d2-plugin/blob/master/CHANGELOG.md)
- [Commits](https://github.com/landmaj/mkdocs-d2-plugin/compare/1.5.0...1.6.0)

---
updated-dependencies:
- dependency-name: mkdocs-d2-plugin
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

docs/requirements.txt

@@ -1,5 +1,5 @@
 mkdocs-awesome-pages-plugin==2.9.3
-mkdocs-d2-plugin==1.5.0
+mkdocs-d2-plugin==1.6.0
 mkdocs-git-revision-date-localized-plugin==1.3.0
 mkdocs-material==9.5.49
 mkdocs-minify-plugin==0.8.0