Switching map to tomap for TF v1.4.7

[danielgoff]

WHAT
Updating map to use tomap.

WHY
Upgrading staging API to TF version 1.4.7 causes this output in the plan:

Error: Error in function call
│
│   on .terraform/modules/us_west1_urbncat_celery_mig/main.tf line 63, in resource "google_compute_instance_template" "default":
│   63:     map("startup-script", var.startup_script, "tf_depends_id", var.depends_id),
│     ├────────────────
│     │ while calling map(vals...)
│
│ Call to function "map" failed: the "map" function was deprecated in Terraform v0.12 and is no longer available; use tomap({ ... }) syntax to write a literal map.