Fix dataset URL

Update download URL to a local hub file

bc5cdr.py

@@ -77,8 +77,8 @@ _HOMEPAGE = "http://www.biocreative.org/tasks/biocreative-v/track-3-cdr/"
 _LICENSE = 'Public Domain Mark 1.0'
 
 _URLs = {
-    "source": "http://www.biocreative.org/media/store/files/2016/CDR_Data.zip",
-    "bigbio_kb": "http://www.biocreative.org/media/store/files/2016/CDR_Data.zip",
+    "source": "https://huggingface.co/datasets/bigbio/bc5cdr/resolve/main/CDR_Data.zip",
+    "bigbio_kb": "https://huggingface.co/datasets/bigbio/bc5cdr/resolve/main/CDR_Data.zip",
 }
 
 _SUPPORTED_TASKS = [