fix the yaml file

egs/mustc/asr/conf/basis.yaml

@@ -10,9 +10,10 @@ post-process: sentencepiece
 #maximize_best_checkpoint_metric: False
 
 eval-wer: True
-maximize_best_checkpoint_metric: False
 eval-wer-args: {"beam": 5, "lenpen": 1.0}
 eval-wer-tok-args: {"wer_remove_punct": true, "wer_lowercase": true, "wer_char_level": false}
+best_checkpoint_metric: wer
+maximize_best_checkpoint_metric: False
 
 no-epoch-checkpoints: True
 #keep-last-epochs: 10