changelog: add note on v1.1 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. Upgrade Path.md)).
 
-## Release (unreleased)
-* Under active development
-
+## Release v1.1
 * Add multi-protocol support and version identification to Node API /self and hence Query API /nodes
 * Add 'api\_proto' TXT records to DNS-SD advertisements
 * Add 'api\_ver' TXT records to DNS-SD advertisements