Mark pagination KEP as implemented

Author: wojtek-t

keps/sig-api-machinery/365-paginated-lists/kep.yaml

@@ -6,7 +6,7 @@ authors:
 owning-sig: sig-api-machinery
 participating-sigs:
   - sig-scalability
-status: implementable
+status: implemented
 creation-date: 2017-08-29
 reviewers:
   - "@liggitt"