Add dollar sign prefix

config/services.yaml

@@ -6,10 +6,10 @@ services:
     pcm_icon.icon_extension:
         public: true
         class: Pcm\IconBundle\Twig\Functions\IconExtension
-        args:
-            directories:
+        arguments:
+            $directories:
                 - '%kernel.project_dir%/public/icons'
-            palletes:
+            $palletes:
                 - primary:
                     stroke: stroke-primary,
                     fill: fill-primary