Update pubmed.py

Please update the url since it is outdated

pubmed.py

@@ -39,7 +39,7 @@ _LICENSE = ""
 # The HuggingFace dataset library don't host the datasets but only point to the original files
 # This can be an arbitrary nested dict/list of URLs (see below in `_split_generators` method)
 # Note these URLs here are used by MockDownloadManager.create_dummy_data_list
-_URLs = [f"https://ftp.ncbi.nlm.nih.gov/pubmed/baseline/pubmed22n{i:04d}.xml.gz" for i in range(1, 1115)]
+_URLs = [f"https://ftp.ncbi.nlm.nih.gov/pubmed/baseline/pubmed23n{i:04d}.xml.gz" for i in range(1, 1115)]
 
 
 # Copyright Ferry Boender, released under the MIT license.