For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:kanku:perl/15.6/devel:kanku:perl.repo
zypper refresh
zypper install perl-Dancer2
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:kanku:perl/15.5/devel:kanku:perl.repo
zypper refresh
zypper install perl-Dancer2
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:kanku:perl/15.4/devel:kanku:perl.repo
zypper refresh
zypper install perl-Dancer2