For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:andriinikitin:sypper/openSUSE_Tumbleweed/home:andriinikitin:sypper.repo
zypper refresh
zypper install sypper
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:andriinikitin:sypper/15.6/home:andriinikitin:sypper.repo
zypper refresh
zypper install sypper
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:andriinikitin:sypper/15.5/home:andriinikitin:sypper.repo
zypper refresh
zypper install sypper
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:andriinikitin:sypper/15.4/home:andriinikitin:sypper.repo
zypper refresh
zypper install sypper