Add CHANGELOG entry for v2.1.0

Author: aaron-lane

CHANGELOG.md

@@ -8,6 +8,8 @@ Extending the adopted spec, each change should have a link to its corresponding
 
 ## [Unreleased]
 
+## [v2.1.0] - 2019-05-30
+
 ### Added
 
 * Support for v2.6 and v2.7 of the Google providers. [#152]
@@ -111,7 +113,8 @@ 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/v2.0.1...HEAD
+[Unreleased]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v2.1.0...HEAD
+[v2.1.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v2.0.1...v2.1.0
 [v2.0.1]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v2.0.0...v2.0.1
 [v2.0.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v1.0.1...v2.0.0
 [v1.0.1]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v1.0.0...v1.0.1