Update to version v2.1.0

Author: groverlalit

CHANGELOG.md

@@ -4,7 +4,7 @@ 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).
 
-## [2.1] - 2021-05-15
+## [2.1.0] - 2021-05-15
 ### Added
 - Added option to enable concurrency to deploy StackSets operations in regions in parallel.
 - Added support for UTF-8 encoded CloudFormation templates. [#55](https://github.com/awslabs/aws-control-tower-customizations/issues/55)