Rather than using 7.71.x and 7.72.x, we could instead use main branch as the fallback when 7.72.x is not available.

This would require a change to simplify https://github.com/redhat-developer/devspaces/blob/devspaces-3-rhel-8/product/updateVersionAndRegistryTags.sh so that the -1 branch is always just main branch.

At the same time, we can adjust the math again since we're now going back to 3 week sprints.