Update bias_auc.py

changed type to metric

bias_auc.py

@@ -33,7 +33,7 @@ label list[int]: list containing label index for each item
 output list[list[float]]: list of model output values for each 
 """
 
-class BiasAUC(evaluate.EvaluationModule):
+class BiasAUC(evaluate.Metric):
     def _info(self):
         return datasets.MetricInfo(
             description=_DESCRIPTION,