panel convert to card

resource/locales/en-US/welcome.md

@@ -3,9 +3,9 @@
 [![GitHub Releases](https://img.shields.io/github/release/weseek/growi.svg)](https://github.com/weseek/growi/releases/latest)
 [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](LICENSE)
 
-<div class="panel panel-primary">
-  <div class="panel-heading">Tips</div>
-  <div class="panel-body"><ul>
+<div class="card">
+  <div class="card-header">Tips</div>
+  <div class="card-body"><ul>
     <li>Ctrl(⌘)-/ to show quick help</li>
     <li>You can write HTML with <a href="https://getbootstrap.com/docs/3.3/css/">Bootstrap 3</a>.</li>
   </ul></div>

resource/locales/ja/welcome.md

@@ -3,9 +3,9 @@
 [![GitHub Releases](https://img.shields.io/github/release/weseek/growi.svg)](https://github.com/weseek/growi/releases/latest)
 [![MIT License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](LICENSE)
 
-<div class="panel panel-primary">
-  <div class="panel-heading">Tips</div>
-  <div class="panel-body"><ul>
+<div class="card">
+  <div class="card-header">Tips</div>
+  <div class="card-body"><ul>
     <li>Ctrl(⌘)-/ でショートカットヘルプを表示します</li>
       <li>HTML/CSS の記述時は、<a href="https://getbootstrap.com/docs/3.3/css/">Bootstrap 3</a> を利用できます</li>
   </ul></div>