Update CHANGELOG.md in preparation for 0.2.0 release

Author: ponylang-main

CHANGELOG.md

@@ -2,18 +2,12 @@
 
 All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org/) and [Keep a CHANGELOG](http://keepachangelog.com/).
 
-## [unreleased] - unreleased
-
-### Fixed
-
+## [0.2.0] - 2025-01-22
 
 ### Added
 
 - Add JsonExtractor utility class ([PR #19](https://github.com/ponylang/json/pull/19))
 
-### Changed
-
-
 ## [0.1.0] - 2023-02-10
 
 ### Added