For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/network:ha-clustering:Unstable/openSUSE_Tumbleweed/network:ha-clustering:Unstable.repo
zypper refresh
zypper install rubygem-sass-listen
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/network:ha-clustering:Unstable/15.6/network:ha-clustering:Unstable.repo
zypper refresh
zypper install rubygem-sass-listen
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/network:ha-clustering:Unstable/15.5/network:ha-clustering:Unstable.repo
zypper refresh
zypper install rubygem-sass-listen
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/network:ha-clustering:Unstable/15.4/network:ha-clustering:Unstable.repo
zypper refresh
zypper install rubygem-sass-listen