Bump grunt-purescript dependency

Author: paf31

package.json

@@ -9,6 +9,6 @@
   "dependencies": {
     "grunt": "~0.4.4",
     "grunt-contrib-clean": "~0.5.0",
-    "grunt-purescript": "~0.5.0"
+    "grunt-purescript": "~0.6.0"
   }
 }