Fix PureScript dependency version

Author: garyb

package.json

@@ -10,7 +10,7 @@
     "jshint": "^2.9.4",
     "pulp": "^11.0.0",
     "purescript-psa": "^0.5.0",
-    "purescript": "^0.11.2",
+    "purescript": "^0.11.1",
     "rimraf": "^2.6.1"
   }
 }