security(deps): update mkdocs requirement from >=1.5.0 to >=1.6.1 (#507)

Updates the requirements on [mkdocs](https://github.com/mkdocs/mkdocs) to permit the latest version.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](https://github.com/mkdocs/mkdocs/compare/1.5.0...1.6.1)

---
updated-dependencies:
- dependency-name: mkdocs
  dependency-version: 1.6.1
  dependency-type: direct:production
...

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

requirements-docs.txt

@@ -1,4 +1,4 @@
-mkdocs>=1.5.0
+mkdocs>=1.6.1
 mkdocs-material>=9.7.6
 mkdocs-minify-plugin>=0.7.0
 mkdocs-mermaid2-plugin>=1.2.3