修改README，添加数据示例

PaddleNLP/ELMO/run.sh

-export CUDA_VISIBLE_DEVICES=4 
+export CUDA_VISIBLE_DEVICES=0 
 python  train.py \
 --train_path='data/train/sentence_file_*'  \
 --test_path='data/dev/sentence_file_*'  \

PaddleNLP/ELMO/train.py

@@ -578,8 +578,6 @@ def train_loop(args,
 
         end_time = time.time()
         total_time += end_time - start_time
-        logger.info("train ppl {}".format(ppl))
-
         if epoch_id == args.max_epoch - 1 and args.enable_ce:
             logger.info("lstm_language_model_duration\t%s" %
                         (total_time / args.max_epoch))