title: Assigning IAM Policy to an existing Cloud Build Service Account in Google cloud using terraform fails
body: <p>I am trying to assign a IAM policy document to an existing Cloud Build Service Account, but its failing for some reason.
  following is my iam policy</p>
  <pre><code>data &quot;google_iam_policy&quot; &quot;vulznotepolicy&quot; {
  binding {
    role = &quot;roles/containeranalysis.notes.occurrences.viewer&quot;
  
    members = [
    &quot;serviceaccount:&lt;project_number&gt;@cloudbuild.gserviceaccount.com&quot;
    ]
   }
  }
  </code></pre>
  <p>following is policy assignment to Service account</p>
  <pre><code>resource &quot;google_service_account_iam_policy&quot; &quot;buildsa&quot; {
  service_account_id = &quot;serviceaccount:&lt;project_number&gt;@cloudbuild.gserviceaccount.com&quot;
  policy_data        = data.google_iam_policy.vulznotepolicy.policy_data
  }
  </code></pre>
  <p>service account id doesn't accept the format that i have provided. I have given just the &lt;project_number&gt; still it doesn't accept. Not sure what the issue is</p>