How to override file t3bootstrap.tpl.php

Hello everyone,
I need to add some additional classes and attributes to Menu Heading item, after trying to do it in regular way of overriding a module, since I thought that it's mod_menu. I found out that in fact this file (/plugins/system/t3/includes/menu/t3bootstrap.tpl.php) is the one generating the menu. My issue is, that on first update the changes I made to this file could be overwritten.

So, how do I override this file?