Add service_account to google_cloudbuild_trigger

[modular-magician]

Fix hashicorp/terraform-provider-google#10053.

Add service_account to google_cloudbuild_trigger (Included in the REST documentation).

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• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

cloudbuild: added field `service_account` to `google_cloudbuild_trigger`

Derived from GoogleCloudPlatform/magic-modules#5237

[maniimanjari]

terraform {
required_providers {
google = {
version = "~> 3.0.0-beta.1"
}
}
}
provider "google" {
project = var.project_id
region = var.location
}
resource "google_service_account" "service_account" {
account_id = "cloudrun"
display_name = "Service Account to deploy apps to cloudrun"
project = var.project_id
}
locals{
rolesList = toset (["roles/run.developer","roles/storage.objectAdmin", "roles/cloudoptimization.serviceAgent", "roles/iam.serviceAccountUser", "roles/artifactregistry.writer" ])
}

resource "google_project_iam_binding" "cloud_build_sa" {
for_each = local.rolesList
project = var.project_id
role = each.key
members = [
"serviceAccount:${google_service_account.service_account.email}"
]
}
resource "google_cloudbuild_trigger" "Trigger" {
provider = google
github {
owner = var.Repo_Org
name = var.Repo_Name
push {
branch = var.branch_env
}
}
name = "${var.Repo_Name}-${var.branch_env}"
description = "Deploy Trigger for ${var.Repo_Name} to cloud-run"
filename = "cloudbuild.yaml"
service_account = "projects/${var.project_id}/serviceAccounts/${google_service_account.service_account.email}"
}

This throws errors listed below
Error: Insufficient trigger_template blocks
│
│ on main.tf line 38, in resource "google_cloudbuild_trigger" "Trigger":
│ 38: resource "google_cloudbuild_trigger" "Trigger" {
│
│ At least 1 "trigger_template" blocks are required.
╵
╷
│ Error: Unsupported block type
│
│ on main.tf line 40, in resource "google_cloudbuild_trigger" "Trigger":
│ 40: github {
│
│ Blocks of type "github" are not expected here.
╵
╷
│ Error: Unsupported argument
│
│ on main.tf line 52, in resource "google_cloudbuild_trigger" "Trigger":
│ 52: service_account = "****"
│
│ An argument named "service_account" is not expected here.

Can you please correct me here ? I need to use github but not trigger_template