[aur-general] Deprecation of 'gimp-plugin-deskew' package

The 'gimp-plugin-deskew' AUR package (https://aur.archlinux.org/packages.php?ID=34210) is deprecated, since it's sources are invalid. I have submitted the 'gimp-plugin-deskew-git' package to replace it. I suggest that the non-git package is removed, to prevent confusion.