Add CHANGELOG entry

Author: samwelkanda

CHANGELOG.md

@@ -5,6 +5,14 @@ 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).
 
+## [1.2.0] - 2024-03-19
+
+### Added
+- Added support for form and multipart serialization.
+
+### Changed
+ - Latest metadata updates from 24th March 2024.
+
 ## [1.1.0] - 2024-01-24
 
 ### Added