It is valid to run `git-webkit publish` without a novel branch. This is the case when the caller of `git-webkit` intends to publish tags along an existing branch. Support that workflow.
<rdar://problem/116092404>
Pull request: https://github.com/WebKit/WebKit/pull/18260
Committed 268536@main (f90c4a57393f): <https://commits.webkit.org/268536@main> Reviewed commits have been landed. Closing PR #18260 and removing active labels.