update changelog

Author: andrzejewsky

CHANGELOG.md

@@ -5,7 +5,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [1.11.0] - UNRELEASED
+## [1.11.0] - 2019.12.20
 
 ### Added
 - Add unit tests for `core/modules/url` - @dz3n (#3469)