rubygem-url_safe_base64 from openSUSE:Leap:15.1 project

需要 standard ，用 root 執行：

zypper addrepo https://download.opensuse.org/repositories/openSUSE:Leap:15.1/standard/openSUSE:Leap:15.1.repo
zypper refresh
zypper install rubygem-url_safe_base64