build(deps): update mkdocs requirement from ~=1.6.0 to ~=1.6.1

Updates the requirements on [mkdocs](https://github.com/mkdocs/mkdocs) to permit the latest version.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](mkdocs/mkdocs@1.6.0...1.6.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

requirements-docs.txt

@@ -1,5 +1,5 @@
 markdown-include~=0.8.1
-mkdocs~=1.6.0
+mkdocs~=1.6.1
 mkdocs-material~=9.5.26
 pygments~=2.18.0
 pymdown-extensions~=10.8.1