changelog for v0.4.21

Author: TheAngryByrd

CHANGELOG.md

@@ -4,6 +4,11 @@ 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).
 
+## [0.4.21] - 29.10.2023
+
+### Fixed
+* [Fix WorkDoneProgressCancel arguments](https://github.com/ionide/LanguageServerProtocol/pull/58) (thanks @TheAngryByrd)
+
 ## [0.4.20] - 28.10.2023
 
 ### Changed