fix(runner/local): use of removed property (#83)

The local dag runner still used `ColumnNames.prediction`, which no longer exists due to multiple target support.

crunch/runner/local.py

@@ -212,8 +212,7 @@ def dag_loop(
                 prediction,
                 self.column_names.id,
                 None,
-                # TODO .prediction does not exists anymore
-                self.column_names.prediction,
+                self.column_names.outputs,
             )
 
         return prediction