Add pooch downloader to workaround readthedocs/readthedocs.org#11763 (#547)

Author: znichollscr

cf_xarray/utils.py

@@ -108,10 +108,16 @@ def parse_cf_standard_name_table(source=None):
     if not source:
         import pooch
 
+        downloader = pooch.HTTPDownloader(
+            # https://github.com/readthedocs/readthedocs.org/issues/11763
+            headers={"User-Agent": "cf-xarray"}
+        )
+
         source = pooch.retrieve(
             "https://raw.githubusercontent.com/cf-convention/cf-convention.github.io/"
             "master/Data/cf-standard-names/current/src/cf-standard-name-table.xml",
             known_hash=None,
+            downloader=downloader,
         )
     root = ElementTree.parse(source).getroot()