Add v1.2.0 changelog link

Author: kristjanvalur

CHANGELOG.md

@@ -99,6 +99,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - GitHub Actions CI for automated building and testing
 - Visual Studio project files (VS2017, VS2019, VS2022)
 
+[1.2.0]: https://github.com/stackless-dev/stackman/releases/tag/v1.2.0
 [1.1.0]: https://github.com/stackless-dev/stackman/releases/tag/v1.1.0
 [1.0.1]: https://github.com/stackless-dev/stackman/releases/tag/v1.0.1
 [1.0.0]: https://github.com/stackless-dev/stackman/releases/tag/v1.0.0