Now depends on billiard 3.3.0.18

requirements/default.txt

@@ -1,3 +1,3 @@
 pytz>dev
-billiard>=3.3.0.17,<3.4
+billiard>=3.3.0.18,<3.4
 kombu>=3.0.21,<3.1

setup.cfg

@@ -11,7 +11,7 @@ upload-dir = docs/.build/html
 
 [bdist_rpm]
 requires = pytz >= 2011b
-           billiard >= 3.3.0.17
+           billiard >= 3.3.0.18
            kombu >= 3.0.21
 
 [wheel]