Merge pull request kubernetes#715 from marpaia/graduation-is-a-kep

Add stage graduation to the list of issues that require a KEP

README.md

@@ -12,6 +12,7 @@ An enhancement is anything that:
 
 - a blog post would be written about after its release (ex. [minikube](https://kubernetes.io/blog/2016/07/minikube-easily-run-kubernetes-locally/), [StatefulSets](https://kubernetes.io/blog/2016/07/thousand-instances-of-cassandra-using-kubernetes-pet-set/), [rkt container runtime](https://kubernetes.io/blog/2016/07/rktnetes-brings-rkt-container-engine-to-kubernetes/))
 - requires multiple parties/SIGs/owners participating to complete (ex. GPU scheduling [API, Core, & Node], StatefulSets [Storage & API])
+- will be graduating from one stage to another (ex. alpha to beta, beta to GA)
 - needs significant effort or changes Kubernetes in a significant way (ex. something that would take 10 person-weeks to implement, introduce or redesign a system component, or introduces API changes)
 - impacts the UX or operation of Kubernetes substantially such that engineers using Kubernetes will need retraining
 - users will notice and come to rely on