Update CHANGELOG.md

Author: morgante

CHANGELOG.md

@@ -15,6 +15,7 @@ Extending the adopted spec, each change should have a link to its corresponding
 ### 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]
+* Add a parameter `registry_project_id` to allow connecting to registries in other projects. [#273]
 
 ## [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).
@@ -204,6 +205,7 @@ 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
 
+[#273]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/273
 [#247]: https://github.com/terraform-google-modules/terraform-google-kubernetes-engine/pull/247
 [#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