`disk_name` value not used when creating disk instance

[sestegra]

Overview of the Issue

The disk_name value isn't used by Packer when creating the VM instance's boot disk.

Reproduction Steps

Plugin and Packer version

Packer v1.7.6 googlecompute = 1.0.5

Simplified Packer Buildfile

source "googlecompute" "windows" {
  # Google Cloud parameters
  project_id   = var.gcp_project_id
  zone         = var.gcp_zone
  subnetwork   = var.gcp_subnetwork
  account_file = var.gcp_account_file

  # Builder VM parameters
  instance_name = var.builder_instance_name
  source_image  = var.builder_image
  machine_type  = var.builder_machine_type
  disk_name     = "${var.builder_instance_name}-c"
  disk_size     = var.builder_disk_size
}

Operating system and Environment details

macOS 11.6 (20G165)

Log Fragments and crash.log files

No relevant information in logs