Update CHANGELOG.md

Author: morgante

CHANGELOG.md

@@ -8,6 +8,10 @@ Extending the adopted spec, each change should have a link to its corresponding
 
 ## [Unreleased]
 
+### Added
+
+* Added [private](https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/tree/master/modules/private-cluster-update-variant) and [beta private](https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/tree/master/modules/beta-private-cluster-update-variant) variants which allow node pools to be created before being destroyed. [#256]
+
 ## [v5.0.0] - 2019-09-25
 v5.0.0 is a backwards-incompatible release. Please see the [upgrading guide](./docs/upgrading_to_v5.0.md).
 
@@ -196,6 +200,7 @@ In either case, upgrading to module version `v1.0.0` will trigger a recreation o
 [v0.3.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v0.2.0...v0.3.0
 [v0.2.0]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/compare/v0.1.0...v0.2.0
 
+[#256]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/256
 [#248]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/248
 [#228]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/228
 [#238]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/238