Customized the testimonials.php

Hi,

We have been using this plugin and we love it a lot. However,
we have customized the testimonials.php of the plugin a bit to meet the client’s requirement/needs. (just the arrangement of the widget and single page testimonial)

How can I disable the plugin update to prevent overriding of the customizations done?

https://www.ads-software.com/plugins/gc-testimonials/