Prepare release v2.1.0

Author: Maxim Bovtunov

CHANGELOG.md

@@ -4,6 +4,12 @@ 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).
 
+## v2.1.0
+
+### Added
+
+- Visualization
+
 ## v2.0.1
 
 ### Added