Updated for Focal

Hi, I'm going through all the Xenial apps that didn't get updated to focal, and updating them. If you are willing to accept this pull request and update the app in the open-store, that would be great! Tested on a Fair Phone 4.

If you are not able or willing, or just want a break from this, I can fork the project and make my own update in the open-store, if that's easier for you.

Or if you feel this app no longer should continue for some reason, please let me know.

Please let me know how I can help, and thanks for making this awesome app for UT!