fix(switch): non working vue component

Author: farfromrefug

src/switch/vue/index.ts

@@ -5,7 +5,12 @@ export default {
     install(Vue) {
         if (!installed) {
             installed = true;
-            Vue.registerElement('MDSwitch', () => Switch, {});
+            Vue.registerElement('MDSwitch', () => Switch, {
+                model: {
+                    prop: 'checked',
+                    event: 'checkedChange',
+                }
+            });
         }
     }
 };