trac #34211: replace call to SSLContext with default_context

Author: dcoudert

src/sage/graphs/isgci.py

@@ -831,7 +831,7 @@ def _download_db(self):
         """
         import tempfile
         u = urlopen('https://www.graphclasses.org/data.zip',
-                    context=SSLContext())
+                    context=default_context())
         with tempfile.NamedTemporaryFile(suffix=".zip") as f:
             f.write(u.read())
             z = zipfile.ZipFile(f.name)