The change in !11728 would cause an arbitrary project to be chosen to test
system hooks, and it's likely that the project would not have any commits or
relevant commits to test the hook. This would prevent admins from verifying
that the hook fired. Instead of trying to create a representative hook
dynamically, just send static data to guarantee the hook will actually be
tested.
Closes#37067
When we updated gitlab_git to 10.4.1, `tag.target` changed from pointing
to the sha of the tag to the sha of the commit the tag points to. The
problem is that only annotated tags have `object_sha`s, lightweight tags
don't (it's nil), so (only) in their case we still need to use
`tag.target`.