Update changelog date, update ci workflow Unity version

Author: Edvinas01

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).
 
-## [2.0.0] - 2021-06-08
+## [2.0.0] - 2021-07-06
 This release contains major breaking changes and migrates from 2019 (LTS) to 2020 (LTS) in order to utilise generics.
 
 ### Added