ristretto from X11:xfce:4.19 project

需要 openSUSE Tumbleweed ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/X11:xfce:4.19/openSUSE_Tumbleweed/X11:xfce:4.19.repo
zypper refresh
zypper install ristretto