opentoonz from openSUSE:Backports:SLE-15-SP7 project

需要 standard ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/openSUSE:Backports:SLE-15-SP7/standard/openSUSE:Backports:SLE-15-SP7.repo
zypper refresh
zypper install opentoonz