[UPDATE] Add some papers

[jacksonchen1998]

Hello

I have added some papers.

• Contrastive Energy Prediction for Exact Energy-Guided Diffusion Sampling in Offline Reinforcement Learning
• Offline Reinforcement Learning via High-Fidelity Generative Behavior Modeling
• Goal-Conditioned Imitation Learning using Score-based Diffusion Policies

Please check

[YinminZhang]

Certainly, I can respond to your pull request.

Thank you for submitting a new paper about the diffusion model in RL. It is great to see new research being contributed to the field.

I will go ahead and merge your pull request into the repository. Thank you again for your contribution, and please feel free to submit more changes in the future.