While it's not happening today, we'll want to eventually also handle
updates to this CHANGELOG list via krel changelog. By collapsing the set
of changelogs into a single list, it will be a little easier to write
out an updated file for commit by searching the contents of the directory
that match "CHANGELOG-x.y.md" and adding them to the list.
Signed-off-by: Stephen Augustus <saugustus@vmware.com>