For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:markusd:samba:samba-4.21-related:samba-4.21-heimdal-dc/openSUSE_Tumbleweed/home:markusd:samba:samba-4.21-related:samba-4.21-heimdal-dc.repo
zypper refresh
zypper install samba-winbind
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:markusd:samba:samba-4.21-related:samba-4.21-heimdal-dc/15.6/home:markusd:samba:samba-4.21-related:samba-4.21-heimdal-dc.repo
zypper refresh
zypper install samba-winbind