Now depends on kombu 3.0.33

Changelog

@@ -10,6 +10,10 @@ new in Celery 3.1.
 
 .. _version-3.1.20:
 
+- **Requirements**
+
+    - Now depends on :ref:`Kombu 3.0.33 <kombu:version-3.0.33>`.
+
 Documentation fixes:
 
     Contributed by

requirements/default.txt

@@ -1,3 +1,3 @@
 pytz>dev
 billiard>=3.3.0.21,<3.4
-kombu>=3.0.29,<3.1
+kombu>=3.0.33,<3.1