Для openSUSE Tumbleweed запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:libraries:libyui/openSUSE_Tumbleweed/devel:libraries:libyui.repo
zypper refresh
zypper install rubygem-regexp_parser
Для openSUSE Factory запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:libraries:libyui/openSUSE_Factory/devel:libraries:libyui.repo
zypper refresh
zypper install rubygem-regexp_parser
Для 15.6 запустите от имени root:
zypper addrepo https://download.opensuse.org/repositories/devel:libraries:libyui/15.6/devel:libraries:libyui.repo
zypper refresh
zypper install rubygem-regexp_parser