changelog: update for v1.3 release

CHANGELOG.md

@@ -1,9 +1,7 @@
 # Changelog
 This document provides an overview of changes between released versions of this specification. It is particularly important to consider this when implementing Registration and Query APIs which may support multiple releases simultaneously to ease upgrades in large facilities (see [Upgrade Path](docs/6.0.%20Upgrade%20Path.md)).
 
-## Release (unreleased)
-* Under active development
-
+## Release v1.3
 * Add additional network data for Nodes as required by IS-06
 * Deprecate mDNS announcements for Nodes in registered mode
 * Replace DNS-SD service type for Registration API