Fix metadata schema v1

- The old version works (by miracle :), but it's a non valid Json.

Signed-off-by: Ulysses Souza <ulysses.souza@docker.com>

Author: Ulysses Souza

specification/schemas/metadata_schema_v0.1.json

@@ -74,4 +74,5 @@
                 }
             }
         }
+    }
 }