Note: google_service_account_iam_policy cannot be used in conjunction with google_service_account_iam_binding and google_service_account_iam_member or they will fight over what your policy should be.
Note: google_service_account_iam_binding resources can be used in conjunction with google_service_account_iam_member resources only if they do not grant privilege to the same role.
See https://www.terraform.io/docs/providers/google/r/google_service_account_iam.html