Upgrade ply
diff --git a/requirements.txt b/requirements.txt
index 7e336cd..fccedf6 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 cssmin==0.2.0
-ply==3.10
+ply==3.11
 pyScss==1.3.5
 slimit==0.8.1
 webassets==0.12.1