Release 0.20 Changelog.

Author: Diptorup Deb

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).
 
-## Unreleased
+## [0.20.0] - 2023-03-06
 
 ### Added
 * New dpjit decorator supporting dpnp compilation (#887)