docs: update CHANGELOG.md [skip ci]

Author: JCMais

CHANGELOG.md

@@ -201,7 +201,8 @@ Special Thanks to [@koskokos2](https://github.com/koskokos2) for their contribut
 - Improved code style, started using prettier
 ## [1.2.0] - 2017-08-28
 
-[Unreleased]: https://github.com/JCMais/node-libcurl/compare/v2.1.0...HEAD
+[Unreleased]: https://github.com/JCMais/node-libcurl/compare/v2.1.1...HEAD
+[2.1.1]: https://github.com/JCMais/node-libcurl/compare/v2.1.0...v2.1.1
 [2.1.0]: https://github.com/JCMais/node-libcurl/compare/v2.0.3...v2.1.0
 [2.0.3]: https://github.com/JCMais/node-libcurl/compare/v2.0.2...v2.0.3
 [2.0.2]: https://github.com/JCMais/node-libcurl/compare/v2.0.1...v2.0.2