Update CHANGELOG.md

Author: alshan

CHANGELOG.md

@@ -5,9 +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).
 
-## [Unreleased]
-
-## [1.1.0] - 2020-11-xx
+## [1.1.0] - 2020-11-20
 ### Added
  - GeoTools support (see [geotools.md](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/geotools.md)).
  - API for tooltip customization (see [tooltips.md](https://github.com/JetBrains/lets-plot-kotlin/blob/master/docs/tooltips.md)).