Switching default build node to centos8-builder-4c-4g
we are currently defaulting to centos7-builder-4c-4g here: https://github.com/opendaylight/releng-builder/blob/master/jjb/defaults.yaml#L19=
CentOS7 is ancient and cannot support our releases going forward, as it lacks JDK17 -- which is scheduled to be required for Chlorine.
MRI projects have already switched to CentOS (Stream) 8, like here: https://github.com/opendaylight/releng-builder/blob/master/jjb/netconf/netconf.yaml#L17=
That having been said and provided we get a fix for https://jira.linuxfoundation.org/plugins/servlet/theme/portal/2/IT-23826, I propose we switch the default build node to CentOS 8 and deal with whatever fallout -- probably in June, as that is essentially quiet with only Chlorine prep on the table.