Update dependency mkdocs-material to v9.1.6 (#97)

Author: slack-oss-bot

.github/workflows/mkdocs-requirements.txt

@@ -7,7 +7,7 @@ Markdown==3.4.3
 MarkupSafe==2.1.2
 mkdocs==1.4.2
 mkdocs-macros-plugin==0.7.0
-mkdocs-material==9.1.5
+mkdocs-material==9.1.6
 mkdocs-material-extensions==1.1.1
 Pygments==2.14.0
 pymdown-extensions==9.11