Consider providing ueberzug with ueberzugpp as it used to in AUR

ueberzugpp is described as Drop in replacement for ueberzug written in C++. The AUR package that was here before moving to extra therefore was using the provides clause to have it satisfy the ueberzug dependency.

I don't know why, but that clause got removed when ueberzugpp was moved to extra. For people like me who used ueberzugpp to replaceueberzug (which wasn't maintained anymore back then) that means we can't upgrade ueberzugpp if some of our packages depends on ueberzug as it breaks dependencies without that clause. Until ueberzugpp cease to be a drop-in replacement, we should be able to use it as if it was ueberzug (unless maybe, not that developpment on ueberzug have resumed, it's not on-par with it anymore).

I can submit a MR if wanted (I was just surprised when going into that section that it offers me to send an email, so I don't know if forks are preferred, emails and so on).