Add missing link to CHANGELOG.md

Signed-off-by: Remy Suen <remy.suen@gmail.com>

Author: rcjsuen

CHANGELOG.md

@@ -505,6 +505,7 @@ All notable changes to this project will be documented in this file.
 - textDocument/formatting
 - textDocument/rangeFormatting
 
+[Unreleased]: https://github.com/rcjsuen/dockerfile-language-server-nodejs/compare/v0.0.23...HEAD
 [0.0.23]: https://github.com/rcjsuen/dockerfile-language-server-nodejs/compare/v0.0.22...v0.0.23
 [0.0.22]: https://github.com/rcjsuen/dockerfile-language-server-nodejs/compare/v0.0.21...v0.0.22
 [0.0.21]: https://github.com/rcjsuen/dockerfile-language-server-nodejs/compare/v0.0.20...v0.0.21