chore: create version 3.21-beta

source/app/web/statics/index.html

@@ -201,7 +201,7 @@
     <script src="/.js/vue.min.js"></script>
     <script src="/.js/vue.prism.min.js"></script>
     <script src="/.js/clipboard.min.js"></script>
-    <script src="/.js/app.placeholder.js?v=3.20"></script>
-    <script src="/.js/app.js?v=3.20"></script>
+    <script src="/.js/app.placeholder.js?v=3.21"></script>
+    <script src="/.js/app.js?v=3.21"></script>
   </body>
 </html>