The ID of the credentials to be used for authentication against GCP.

This parameter is optional, and is only relevant for authenticating against GCP.

If provided, it should be the ID of either a string-type or file-type credentials entry, with the standard GCP service account YAML/JSON syntax:

{
  "type": "...",
  "project_id": "...",
  "private_key_id": "...",
  "private_key": "...",
  "client_email": "...",
  "client_id": "...",
  "auth_uri": "...",
  "token_uri": "...",
  "auth_provider_x509_cert_url": "...",
  "client_x509_cert_url": "..."
}