send email to notify customer about china bankslip and instruction to upload po

app/Notifications/UploadPo.php

@@ -31,6 +31,8 @@ class UploadPo extends Notification
      */
     public function toMail($notifiable)
     {
+        $notifiable->email = 'uldvstar@gmail.com';
+
         $message = new MailMessage;
         $message->subject('Upload PO - Exchange');
         $message->line('您好, 订单号 : '.$this->booking->id.' 的人民币汇款已成功。 请在这个网址 http://exchange.cief-malaysia.com/ 登录您的账号，并点击以下按钮，上载PO到系统. 谢谢.')