Update case.md

docs/case.md

@@ -163,7 +163,7 @@ DCloud有380万开发者，[uni统计](https://tongji.dcloud.net.cn/)覆盖手
  <strong>vivo商城官方小程序：</strong> 支付宝搜索 “vivo”，或鼠标移此查看[小程序码]
  <div class="scan-code-hover">
     <div class="scan-code-hover-box">
-      <img src="https://img.cdn.aliyun.dcloud.net.cn/uniapp/case/vivo-mall.png" alt="二维码获取失败" />
+      <img src="https://img.cdn.aliyun.dcloud.net.cn/uni-app/case/vivo-mall.png" alt="二维码获取失败" />
     </div>
  </div>
 </div>