chore: update gjs example

use camelCase to satisfy types

Author: Aylur

examples/js/simple-bar/widget/Bar.tsx

@@ -16,8 +16,8 @@ function SysTray() {
             <menubutton
                 tooltipMarkup={bind(item, "tooltipMarkup")}
                 usePopover={false}
-                actionGroup={bind(item, "action-group").as(ag => ["dbusmenu", ag])}
-                menuModel={bind(item, "menu-model")}>
+                actionGroup={bind(item, "actionGroup").as(ag => ["dbusmenu", ag])}
+                menuModel={bind(item, "menuModel")}>
                 <icon gicon={bind(item, "gicon")} />
             </menubutton>
         )))}