Update ubuntu.com Terms of Service

This version was recorded after filtering snapshot OpenTermsArchive/contrib-snapshots@51c7c4109617

Author: AmbNum-Bot

ubuntu.com/Terms of Service.md

@@ -227,6 +227,9 @@ The open source software platform that runs everywhere from the smartphone, the
     *   [Containers](https://ubuntu.com/containers)
     *   [Tutorials](https://ubuntu.com/tutorials)
     *   [16-04](https://ubuntu.com/16-04)
+    *   [Observability](https://ubuntu.com/observability)
+        -------------------------------------------------
+        
 
 * * *