Use `refs/remote/<remote-name>/<branch-name>` to avoid a "Fatal: needed a...

    commit_sha=$(git rev-parse --short HEAD)

    if git ls-remote --exit-code --heads origin "${branch_name}"; then

        # The release branch already exists, we need to make sure that our commit is its current tip

        branch_head_sha=$(git rev-parse --verify --short "refs/heads/${branch_name}")

        branch_head_sha=$(git rev-parse --verify --short "refs/remotes/origin/${branch_name}")

        if [[ "${branch_head_sha}" != "${commit_sha}" ]]; then

            echo "The release branch - ${branch_name} - already exists. ${commit_sha}, the commit you chose when "

            echo "launching this release, is not its current HEAD (${branch_head_sha}). This is not allowed: you "