For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:markusd:samba:samba-4.20-related/openSUSE_Tumbleweed/home:markusd:samba:samba-4.20-related.repo
zypper refresh
zypper install krb5
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:markusd:samba:samba-4.20-related/15.6/home:markusd:samba:samba-4.20-related.repo
zypper refresh
zypper install krb5
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:markusd:samba:samba-4.20-related/15.5/home:markusd:samba:samba-4.20-related.repo
zypper refresh
zypper install krb5