Prune references when pulling content updates
--pull flag is specified, Antora should prune references in the cached repository that have been removed from the remote repository. For example, if a branch has been deleted in the remote repository (such as on GitHub), Antora should remove that branch from the cached repository. As of Antora 2.0.0, it does not. This is a regression from Antora 1.x (as a result of the switch to isomorphic-git).
The workaround is to clean Antora's cache (or the cached folder for the repository in question) so that Antora gets a fresh clone of the repository.