Run update.sh

mono/README.md

@@ -14,6 +14,10 @@ WARNING:
 
 -->
 
+# **DEPRECATION NOTICE**
+
+This image is deprecated due to maintainer inactivity (last updated Jun 2022; [docker-library/official-images#12682](https://github.com/docker-library/official-images/pull/12682)).
+
 # Quick reference
 
 -	**Maintained by**: