Mark KEP as implemented.

Author: josephburnett

keps/sig-autoscaling/2702-graduate-hpa-api-to-GA/kep.yaml

@@ -14,7 +14,7 @@ prr-approvers:
   - "@johnbelamaric"
 creation-date: 2021-05-10
 last-updated: 2021-09-08
-status: implementable
+status: implemented
 
 latest-milestone: "v1.23"
 stage: "stable"