Update Selectize to version 0.13.3

Author: blocknotes

app/assets/javascripts/activeadmin/selectize/selectize.js

@@ -1,6 +1,7 @@
 /**
- * selectize.bootstrap2.css (v0.12.6) - Bootstrap 2 Theme
+ * selectize.css (v0.13.3)
  * Copyright (c) 2013–2015 Brian Reavis & contributors
+ * Copyright (c) 2020 Selectize Team & contributors
  *
  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
  * file except in compliance with the License. You may obtain a copy of the License at:
@@ -12,6 +13,7 @@
  * governing permissions and limitations under the License.
  *
  * @author Brian Reavis <brian@thirdroute.com>
+ * @author Ris Adams <selectize@risadams.com>  
  */
 .selectize-control.plugin-drag_drop.multi > .selectize-input > div.ui-sortable-placeholder {
   visibility: visible !important;
@@ -215,6 +217,9 @@
 .selectize-input > input:focus {
   outline: none !important;
 }
+.selectize-input > input[placeholder] {
+  box-sizing: initial;
+}
 .selectize-input::after {
   content: ' ';
   display: block;