Add Sponsor Link

[UnicornsOnLSD]

Changes

This is just a small PR to add @Chaphasilor as Finamp's sponsor destination. I occasionally get emails asking how to sponsor Finamp, so having an obvious link on the repo should help with that.

FUNDING.yml allows listing multiple people, so if you think that any other people should be listed, feel free to add them :)

[UnicornsOnLSD]

It also looks like the landscape has changed a bit on including donation links within apps. A few years ago they'd get mad at you and demand you do it via an in-app purchase, but that rule has been antitrusted to death in the case of pure donations

[Chaphasilor]

I definitely don't want to be listed alone here, to be honest 😅
Sure, I try to invest time into Finamp whenever I'm motivated enough and don't have other things to do, but I don't think I could keep the project going on my own. If @Komodo5197 would be listed too, I'd be much happier with that, since they are what actually keeps the development going.
But overall donations aren't needed; I get enough to cover any Finamp-related expenses, even without my profile being linked anywhere :)