add missing config: root_options

Author: mahasadhu

config/elfinder.php

@@ -78,4 +78,16 @@
 
     'options' => [],
 
+    /*
+    |--------------------------------------------------------------------------
+    | Root Options
+    |--------------------------------------------------------------------------
+    |
+    | These options are merged, together with every root by default.
+    | See https://github.com/Studio-42/elFinder/wiki/Connector-configuration-options-2.1#root-options
+    |
+    */
+    'root_options' => [
+
+    ],
 ];