Fix changelog link for 2.0.0

Author: James Collier

ChangeLog.md

@@ -34,7 +34,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 Initial release
 
-[unreleased]: https://github.com/vibbits/react-2d-molecule/compare/v1.0.2...HEAD
+[unreleased]: https://github.com/vibbits/react-2d-molecule/compare/v2.0.0...HEAD
+[2.0.0]: https://github.com/vibbits/react-2d-molecule/compare/v1.0.2...v2.0.0
 [1.0.2]: https://github.com/vibbits/react-2d-molecule/compare/v1.0.1...v1.0.2
 [1.0.1]: https://github.com/vibbits/react-2d-molecule/compare/v1.0.0...v1.0.1
 [1.0.0]: https://github.com/vibbits/react-2d-molecule/releases/tag/v1.0.0