Bump mkdocs-material from 9.6.7 to 9.6.8 (microsoft#2811)

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.6.7 to 9.6.8.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.6.7...9.6.8)

---
updated-dependencies:
- dependency-name: mkdocs-material
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements-docs.txt

@@ -1,5 +1,5 @@
 mkdocs==1.6.1
-mkdocs-material==9.6.7
+mkdocs-material==9.6.8
 pymdown-extensions==10.14.3
 mike==2.1.3
 mkdocs-git-revision-date-localized-plugin==1.4.4