[Improment] add $toast/$dialog to Vue.prototype (#363)

packages/dialog/index.js

@@ -61,6 +61,8 @@ Dialog.close = () => {
   instance.value = false;
 };
 
+Vue.prototype.$dialog = Dialog;
+
 export default Dialog;
 export {
   DialogComponent as Dialog

packages/toast/index.js

@@ -56,4 +56,6 @@ Toast.clear = () => {
   instance && instance.clear();
 };
 
+Vue.prototype.$toast = Toast;
+
 export default Toast;