feature: updating

[nick1udwig]

Currently, users must be notified out-of-band (i.e. Discord) to update the app.

It would be better if, on start, app checked releases on github for newer version, and, if one is found, notified user with a link, and perhaps button to open releases webpage.

If would be even better still if app automatically downloaded update when found and installed and restarted upon user clicking a button.