update paper link

leaderboard/md.py

@@ -178,7 +178,7 @@ TOP_TEXT = """# RewardBench: Evaluating Reward Models"""
 
 CAPTION_V2 = f"""The *new version* of RewardBench that is based on unseen human data and designed to be substantially more difficult!
 
-[Code](https://github.com/allenai/reward-bench) |  [Eval. Dataset v2](https://huggingface.co/datasets/allenai/reward-bench-2) | [Results v2](https://huggingface.co/datasets/allenai/reward-bench-2-results) | [Paper](https://github.com/allenai/reward-bench/blob/main/paper-v2.pdf) | Total models: {{}} |  Last restart (PST): {current_time}"""
+[Code](https://github.com/allenai/reward-bench) |  [Eval. Dataset v2](https://huggingface.co/datasets/allenai/reward-bench-2) | [Results v2](https://huggingface.co/datasets/allenai/reward-bench-2-results) | [Paper](https://arxiv.org/abs/2506.01937) | Total models: {{}} |  Last restart (PST): {current_time}"""
 
 CAPTION_V1 = f"""The original RewardBench -- the first reward model evaluation.