Bump mkdocs-material from 9.6.20 to 9.6.21 (#57)

Author: dependabot[bot]

pyproject.toml

@@ -29,7 +29,7 @@ dependencies = [
     "mkdocs-autorefs==1.4.3",
     "mkdocs-literate-nav==0.6.2",
     "mkdocs-macros-plugin==1.4.0",
-    "mkdocs-material==9.6.20",
+    "mkdocs-material==9.6.21",
     "mkdocs==1.6.1",
     "mkdocstrings-python==1.18.2",
     "pymdown-extensions==10.16.1",