修改README部分，添加数据示例

PaddleNLP/ELMO/run.sh

-export CUDA_VISIBLE_DEVICES=0 
+export CUDA_VISIBLE_DEVICES=4 
 python  train.py \
---train_path='baike/train/sentence_file_*'  \
---test_path='baike/dev/sentence_file_*'  \
---vocab_path baike/vocabulary_min5k.txt \
+--train_path='data/train/sentence_file_*'  \
+--test_path='data/dev/sentence_file_*'  \
+--vocab_path data/vocabulary_min5k.txt \
 --learning_rate 0.2 \
 --use_gpu True \
 --local True $@