Add links for 1.3.0-beta.4 in CHANGELOG.

Author: chriskrycho

CHANGELOG.md

@@ -238,7 +238,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 * Basic, semi-working functionality.
 
 [ember-cli-typify]: https://github.com/winding-lines/ember-cli-typify
-[unreleased]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.3.0-beta.3...HEAD
+[unreleased]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.3.0-beta.4...HEAD
+[1.3.0-beta.4]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.3.0-beta.3...v1.3.0-beta.4
 [1.3.0-beta.3]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.3.0-beta.2...v1.3.0-beta.3
 [1.3.0-beta.2]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.3.0-beta.1...v1.3.0-beta.2
 [1.3.0-beta.1]: https://github.com/typed-ember/ember-cli-typescript/compare/v1.2.1...v1.3.0-beta.1