Update README.md

Author: zsdonghao

examples/reinforcement_learning/README.md

@@ -108,7 +108,6 @@ The pretrained models and learning curves for each algorithm are stored [here](h
   See David Silver RL Tutorial Lecture 5 - Q-Learning for more details.
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 * **Deep Q-Network (DQN)**
 
@@ -157,8 +156,6 @@ The pretrained models and learning curves for each algorithm are stored [here](h
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