Merge pull request #524 from ballerina-platform/update-change-log

Update changelog

changelog.md

@@ -4,12 +4,15 @@ This file contains all the notable changes done to the Ballerina MIME package th
 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).
 
-## [2.9.0] - 2023-09-15
+## [Unreleased]
 
 ## Changed
+- [Make some of the Java classes proper utility classes](https://github.com/ballerina-platform/ballerina-standard-library/issues/4940)
+
+## [2.9.0] - 2023-09-15
 
+## Changed
 - [Change `com.sun.activation:jakarta.activation` to `jakarta.activation:jakarta.activation-api`](https://github.com/ballerina-platform/ballerina-standard-library/issues/4789)
-- [Make some of the Java classes proper utility classes](https://github.com/ballerina-platform/ballerina-standard-library/issues/4940)
 
 ## [2.6.0] - 2022-02-20