[aur-general] Merge request: plasma-media-center-git ==> plasma-mediacenter-git

plasma-media-center-git uses an outdated git repo, and the latter uses a name matching upstream better. I have just taken over the latter :) https://aur.archlinux.org/packages/plasma-media-center-git/ https://aur.archlinux.org/packages/plasma-mediacenter-git/