Fix up CHANGELOG links

Author: kddnewton

CHANGELOG.md

@@ -128,7 +128,8 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) a
 
 - 🎉 Initial release! 🎉
 
-[unreleased]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.0.0...HEAD
+[unreleased]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.0.1...HEAD
+[2.0.1]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v2.0.0...v2.0.1
 [2.0.0]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v1.2.0...v2.0.0
 [1.2.0]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v1.1.1...v1.2.0
 [1.1.1]: https://github.com/ruby-syntax-tree/syntax_tree/compare/v1.1.0...v1.1.1