https://bugzilla.opensuse.org/show_bug.cgi?id=1251900
It is a packman package. It happens nearly daily that these packages are out of sync. So usual solution: wait or switch vendor back to openSUSE.
Steam doesn’t care from where Mesa is installed (3rd party packman repo or officially openSUSE repo).
I’m using Steam only with the officially provided openSUSE Mesa packages.