⬆ Bump mkdocs-material from 9.6.14 to 9.6.15 (#1424)

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.6.14 to 9.6.15.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.6.14...9.6.15)

---
updated-dependencies:
- dependency-name: mkdocs-material
  dependency-version: 9.6.15
  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

@@ -1,6 +1,6 @@
 -e .
 -r requirements-docs-tests.txt
-mkdocs-material==9.6.14
+mkdocs-material==9.6.15
 mdx-include >=1.4.1,<2.0.0
 mkdocs-redirects>=1.2.1,<1.3.0
 pyyaml >=5.3.1,<7.0.0