Bump mkdocs-material from 9.1.14 to 9.1.15

Bumps [mkdocs-material](https://github.com/squidfunk/mkdocs-material) from 9.1.14 to 9.1.15.
- [Release notes](https://github.com/squidfunk/mkdocs-material/releases)
- [Changelog](https://github.com/squidfunk/mkdocs-material/blob/master/CHANGELOG)
- [Commits](squidfunk/mkdocs-material@9.1.14...9.1.15)

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

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

Author: dependabot[bot]

pyproject.toml

@@ -47,7 +47,7 @@ docs-gen = [
   "mike == 1.1.2",
   "mkdocs-gen-files == 0.5.0",
   "mkdocs-literate-nav == 0.6.0",
-  "mkdocs-material == 9.1.14",
+  "mkdocs-material == 9.1.15",
   "mkdocs-section-index == 0.3.5",
   "mkdocstrings[python] == 0.21.2",
 ]