OS version for containers on Harbor (hub.opensciencegrid.org)

[aowen-uwmad]

Noticed that containers in https://hub.opensciencegrid.org/harbor/projects/883/repositories are using CentOS 8 Stream, which I believe is at EOL (or something; we are upgrading CHTC APs/EPs from 8 to 9).
Probably want to update the containers to use a newer OS as well.
Thoughts on having containers for different OS versions?

[bbockelm]

I think we should be able to fairly trivially re-base onto the OSG-provided versions of EL9.

@jhiemstrawisc - can you think of anything that would go wrong with this? Should we just open a ticket for 7.9.0 and call it a day?

[jhiemstrawisc]

I don't foresee any issues with this, but we won't know until we try. I'll make a ticket so we can get this done in the next release.

[haoming29]

This issued is addressed in #1199