add missing translation

src/messages/cn/admin.php

@@ -412,4 +412,5 @@
  'aw_requestinsight_toggle_error' => 'Error while enabling Request Insight.',
  'aw_requestinsight_cleared' => 'Data has been cleared.',
  'aw_requestinsight_default_label' => 'Request Insight',
+ 'login_browsehappy' => 'You are using an <strong>outdated</strong> browser. Please <a href="https://browsehappy.com/" target="_blank">upgrade your browser</a> to improve your experience and security.',
 ];