update changelog

Author: izolate

CHANGELOG.md

@@ -4,6 +4,10 @@ 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).
 
+## [6.0.0] - 2023-03-11
+- Dropped `decimalSeparator` option. (**BREAKING CHANGE**)
+- Added `locales` option to format number into different languages.
+
 ## [5.0.1] - 2022-09-11
 ### Fixed
 - Ensured `MillifyOptions` interface is published to npm