kep-3221: update status

Signed-off-by: Rita Zhang <[email protected]>

Author: ritazh

keps/sig-auth/3221-structured-authorization-configuration/kep.yaml

@@ -5,7 +5,7 @@ authors:
   - "@palnabarun"
   - "@ritazh"
 owning-sig: sig-auth
-status: implementable
+status: implemented
 creation-date: 2022-06-21
 reviewers:
   - "@deads2k"