Fix lsun link

Author: NicolasHug

torchvision/datasets/lsun.py

@@ -55,7 +55,7 @@ def __len__(self) -> int:
 
 
 class LSUN(VisionDataset):
-    """`LSUN <https://www.yf.io/p/lsun>`_ dataset.
+    """`LSUN <https://paperswithcode.com/dataset/lsun>`_ dataset.
 
     You will need to install the ``lmdb`` package to use this dataset: run
     ``pip install lmdb``