fix: un-inline example update-destination

spec/submission-api.yaml

@@ -195,6 +195,8 @@ components:
       $ref: './examples/jwk-verify.yaml'
     JWKWrapKey:
       $ref: './examples/jwk-wrapKey.yaml'
+    UpdateDestination:
+      $ref: './examples/update-destination.yaml'
     PatchDestinationStatus:
       $ref: './examples/patch-destination-status.yaml'
     PatchDestinationContact: