update layui version

templates/admin/header.php

@@ -6,11 +6,11 @@
   <meta name="renderer" content="webkit"/>
   <meta name="force-rendering" content="webkit"/>
   <title>OneNav后台管理</title>
-  <link rel='stylesheet' href='static/layui/css/layui.css'>
+  <link rel='stylesheet' href='static/layui/css/layui.css?v=2.8'>
   <link rel='stylesheet' href='templates/admin/static/style.css?v=<?php echo $version; ?>'>
   <link rel="stylesheet" href="static/font-awesome/4.7.0/css/font-awesome.css">
   <script src = 'static/js/jquery.min.js'></script>
-  <script src = 'static/layui/layui.js'></script>
+  <script src = 'static/layui/layui.js?v=2.8'></script>
   <script src="static/js/md5.min.js"></script>
   <script src = "static/js/clipBoard.min.js"></script>
   <script src="templates/admin/static/embed.js?v=<?php echo $version; ?>"></script>