add retrying to requirements

Kully · Kully · commit e063a9d6a8aa · 2018-03-08T12:59:09.000-05:00
diff --git a/optional-requirements.txt b/optional-requirements.txt
@@ -32,4 +32,7 @@ ipykernel
 ## deps for _county_choropleth.py figure factory
 pyshp
 geopandas
-shapely
+shapely
+
+## retrying requests
+retrying
