CHANGELOG.md: k8s v1.12.3 bump (#829)

* CHANGELOG.md: k8s v1.12.3 bump

* CHANGELOG.md: controller-runtime version update note

Author: estroz

CHANGELOG.md

@@ -4,6 +4,9 @@
 
 ### Changed
 
+- The SDK's Kubernetes Golang dependency versions/revisions have been updated from `v1.11.2` to `v1.12.3`. ([#807](https://github.com/operator-framework/operator-sdk/pull/807))
+- The controller-runtime version has been updated from `v0.1.4` to `v0.1.8`. See the `v0.1.8` [release notes](https://github.com/kubernetes-sigs/controller-runtime/releases/tag/v0.1.8) for details.
+
 ### Deprecated
 
 ### Removed