For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:manfred-h:devel:kubic/openSUSE_Tumbleweed/home:manfred-h:devel:kubic.repo
zypper refresh
zypper install helmfile
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:manfred-h:devel:kubic/15.6/home:manfred-h:devel:kubic.repo
zypper refresh
zypper install helmfile
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:manfred-h:devel:kubic/15.5/home:manfred-h:devel:kubic.repo
zypper refresh
zypper install helmfile