For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-M/openSUSE_Tumbleweed/devel:languages:perl:CPAN-M.repo
zypper refresh
zypper install perl-Mojolicious-Plugin-OAuth2
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-M/15.6/devel:languages:perl:CPAN-M.repo
zypper refresh
zypper install perl-Mojolicious-Plugin-OAuth2
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/devel:languages:perl:CPAN-M/15.5/devel:languages:perl:CPAN-M.repo
zypper refresh
zypper install perl-Mojolicious-Plugin-OAuth2