Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-J/openSUSE_Tumbleweed/devel:languages:perl:CPAN-J.repo
zypper refresh
zypper install perl-JSON-RPC
Для 15.5 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-J/15.5/devel:languages:perl:CPAN-J.repo
zypper refresh
zypper install perl-JSON-RPC
Для 15.4 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-J/15.4/devel:languages:perl:CPAN-J.repo
zypper refresh
zypper install perl-JSON-RPC