Prepare the release: bump version, build packages, ...

def prepare(ctx, new_version=None, version_part=None, hide=True,
            dry_run=False):
    """Prepare the release: bump version, build packages, ..."""
    if new_version is not None:
        bump_version(ctx, new_version, version_part=version_part,
                     dry_run=dry_run)
    build_packages(ctx, hide=hide)
    packages = ensure_packages_exist(ctx, check_only=True)
    print_packages(packages)