Add changelog diff links

Author: olivierlacan

CHANGELOG.md

@@ -224,7 +224,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Good examples and basic guidelines, including proper date formatting.
 - Counter-examples: "What makes unicorns cry?".
 
-[unreleased]: https://github.com/olivierlacan/keep-a-changelog/compare/v1.1.0...HEAD
+[unreleased]: https://github.com/olivierlacan/keep-a-changelog/compare/v1.1.1...HEAD
+[1.1.1]: https://github.com/olivierlacan/keep-a-changelog/compare/v1.1.0...v1.1.1
 [1.1.0]: https://github.com/olivierlacan/keep-a-changelog/compare/v1.0.0...v1.1.0
 [1.0.0]: https://github.com/olivierlacan/keep-a-changelog/compare/v0.3.0...v1.0.0
 [0.3.0]: https://github.com/olivierlacan/keep-a-changelog/compare/v0.2.0...v0.3.0