Add Ubuntu 22.04 image w/ root 6.28.00
This image could be used to test Jpp on Ubuntu w/ a (more) recent Root and (more) recent gcc that current images. Note that it's not a "bundle" : only Root is there (and w/o pythia6 even).
(it is basically that one I'm using on my Mac, expect that it's explicitly based on the ARM version of the ubuntu image in my case)