Merge pull request #870 from MiddleFork/master

Fix #869 from cgi import escape fails under python 3.8; import from html instead

Author: minrk

nbviewer/providers/base.py

@@ -12,7 +12,7 @@
 import statsd
 import asyncio
 
-from cgi import escape
+from html import escape
 from contextlib import contextmanager
 from datetime import datetime