Previously, authorization was only checked for ops after the root op.
We also avoid creating empty actions for `assign` and `label`, which
was needed for non-authorized users to be able to create issues/patches.
Previously, COB change commits would not distinguish between their
parents. This means that they would try to load source code commits
(eg. for patch COBs) and then fail since those commits wouldn't have a
manifest or `Rad-Resource`.
We introduce a backwards compatible change here which is that parent
oids that are not COB commits are accompanied by a commit trailer called
`Rad-Related`. This is for all related content that should be pulled in
but is not part of the change graph proper.
When building the change graph, we simply ignore commits that are marked
as "related".
cloudhead