Mark TTL-after-finish KEP to implemented

Author: sahilvv

keps/sig-apps/592-ttl-after-finish/kep.yaml

@@ -7,7 +7,7 @@ authors:
 owning-sig: sig-apps
 participating-sigs:
   - sig-api-machinery
-status: implementable
+status: implemented
 creation-date: 2018-08-16
 reviewers:
   - "@enisoc"