Update to current Android version

[cvzi]

Would you accept a pull request to update this app to a newer Android version?

The app is still available on F-Droid at the moment, but it shows a warning when you try to install it on newer Android versions, because it was built with an SDK that is now considered too old by Google.

I haven't checked how difficult it would be to update it, but I suspect ChatGTP or Github Copilot could do most of it.