This script was provided by Google Compute Image Packages (https://github.com/GoogleCloudPlatform/compute-image-packages) and has been deprecated since over an year. Newer version of the package doesn't include it at all. So remove its usage and instead follow recommended instructions from https://cloud.google.com/compute/docs/disks/add-persistent-disk#formatting.
Google Container-VM Image (GCI)
GCI is a container-optimized OS image for the Google Cloud Platform (GCP). We built GCI primarily for running Google services on GCP. Unlike the open preview version of container-vm, Google Container-VM Image is based on the open source Chromium OS project, allowing us greater control over the build management, security compliance, and customizations for GCP.