For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:tools:scm/openSUSE_Tumbleweed/devel:tools:scm.repo
zypper refresh
zypper install gitea
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:tools:scm/15.5/devel:tools:scm.repo
zypper refresh
zypper install gitea
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:tools:scm/15.4/devel:tools:scm.repo
zypper refresh
zypper install gitea