Updates the change log.

CHANGELOG.md

@@ -27,6 +27,10 @@ BACKWARDS INCOMPATIBILITIES:
 
 IMPROVEMENTS:
 
+* Added new template prepared queries which allow you to define a prefix (possibly even
+  an empty prefix) to apply prepared query features like datacenter failover to multiple
+  services with a single query definition. This makes it easy to apply a common policy to
+  multiple services without having to manage many prepared queries. [GH-1764]
 * Added a new `disable_hostname` configuration option to control whether Consul's
   runtime telemetry gets prepended with the host name. All of the telemetry
   configuration has also been moved to a `telemetry` nested structure, but the old