Bump mkdocs-material from 9.1.2 to 9.1.15 (#1709)

dependabot[bot] · web-flow · commit 75760f8b0a42 · 2023-08-04T18:03:12.000+02:00
diff --git a/requirements/requirements_doc.txt b/requirements/requirements_doc.txt
@@ -1,2 +1,2 @@
 mkdocs==1.4.2
-mkdocs-material==9.1.2
+mkdocs-material==9.1.15
