Link dataset to paper

This PR links the dataset to https://huggingface.co/papers/2404.07987.

Would be great to do this for all artifacts: https://github.com/liming-ai/ControlNet_Plus_Plus?tab=readme-ov-file#%EF%B8%8F-data-preperation

README.md

@@ -19,4 +19,6 @@ dataset_info:
 ---
 # Dataset Card for "MultiGen-20M_train"
 
-[More Information needed](https://github.com/huggingface/datasets/blob/main/CONTRIBUTING.md#how-to-contribute-to-the-dataset-cards)
+Dataset of the paper [ControlNet++: Improving Conditional Controls with Efficient Consistency Feedback](https://huggingface.co/papers/2404.07987)
+
+Github repository: https://github.com/liming-ai/ControlNet_Plus_Plus