For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:smithfarm/openSUSE_Tumbleweed/home:smithfarm.repo
zypper refresh
zypper install perl-Text-Diff
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:smithfarm/15.6/home:smithfarm.repo
zypper refresh
zypper install perl-Text-Diff
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:smithfarm/15.5/home:smithfarm.repo
zypper refresh
zypper install perl-Text-Diff