Add all Packman repo into OpenSuse Leap 15.0:
$ sudo zypper ar -f http://packman.jacobs-university.de/suse/openSUSE_Leap_15.0/ Packman-repo-15.0
Show all repos in OpenSuse:
$ sudo zypper repos
$ sudo zypper install --from [repository] [package]
In my case update gstreamer-plugins-bad-lang package from Packman repo:
$ sudo zypper install --from Packman-repo-15.0 gstreamer-plugins-bad-lang
Change vendor and update all packages from Packman repo:
$ sudo zypper dup --from Packman-repo-15.0
Refresh repo, update packages and upgrade and clean OpenSuse:
$ sudo zypper ref && sudo zypper update -y && sudo zypper dup -y && sudo zypper clean