Add link to Github repository

This PR adds a link to the Github repository: [waltonfuture/MM-UPT](https://github.com/waltonfuture/MM-UPT).

README.md

@@ -12,7 +12,7 @@ pipeline_tag: image-text-to-text
 
 ## Paper Title and Link
 
-The model was presented in the paper [Unsupervised Post-Training for Multi-Modal LLM Reasoning via GRPO](https://huggingface.co/papers/2505.22453).  You can also find the paper on arXiv: [Unsupervised Post-Training for Multi-Modal LLM Reasoning via GRPO (arXiv:2505.22453)](https://arxiv.org/abs/2505.22453)
+The model was presented in the paper [Unsupervised Post-Training for Multi-Modal LLM Reasoning via GRPO](https://huggingface.co/papers/2505.22453). You can also find the paper on arXiv: [Unsupervised Post-Training for Multi-Modal LLM Reasoning via GRPO (arXiv:2505.22453)](https://arxiv.org/abs/2505.22453)
 
 ## Paper Abstract