fix inconsistent data split name

README.md

@@ -64,7 +64,7 @@ To load this dataset via Hugging Face’s `datasets` library:
 from datasets import load_dataset
 
 dataset = load_dataset("neulab/VisualPuzzles")
-data = dataset["test"]
+data = dataset["train"]
 
 sample = data[0]
 print("ID:", sample["id"])