Set release date for v4.1.0 in CHANGELOG

Author: aaron-lane

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 Extending the adopted spec, each change should have a link to its corresponding pull request appended.
 
 ## [Unreleased]
+
+## [v4.1.0] 2019-07-24
+
 ### Added
 
 * Support for GCE cluster resource_labels. [#210]
@@ -147,7 +150,8 @@ Extending the adopted spec, each change should have a link to its corresponding
 
 * Initial release of module.
 
-[Unreleased]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v4.0.0...HEAD
+[Unreleased]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v4.1.0...HEAD
+[v4.1.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v4.0.0...v4.1.0
 [v4.0.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v3.0.0...v4.0.0
 [v3.0.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v2.1.0...v3.0.0
 [v2.1.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v2.0.1...v2.1.0