删除本地存在而远程仓库已经删除的分支

git remote prune origin

prune
Deletes all stale remote-tracking branches under <name>.
These stale branches have already been removed from the
remote repository referenced by <name>, but are still
locally available in "remotes/<name>".

With --dry-run option, report what branches will be pruned,
but do not actually prune them.