Refresh mkdocs dependencies

Author: mdmintz

mkdocs_build/requirements.txt

@@ -14,20 +14,20 @@ click==8.1.3
 ghp-import==2.1.0
 readme-renderer==37.3
 pymdown-extensions==9.11
-importlib-metadata==6.5.0
+importlib-metadata==6.6.0
 pipdeptree==2.7.0
 bleach==6.0.0
 lunr==0.6.2
 nltk==3.8.1
-tornado==6.3
+tornado==6.3.1
 watchdog==3.0.0
 cairocffi==1.5.1
 cairosvg==2.7.0
 cssselect2==0.7.0
 tinycss2==1.2.1
 defusedxml==0.7.1
 mkdocs==1.4.2
-mkdocs-material==9.1.6
+mkdocs-material==9.1.7
 mkdocs-exclude-search==0.6.5
 mkdocs-simple-hooks==0.1.5
 mkdocs-material-extensions==1.1.1