fix: Update int.cloudbuild.yaml to use LR billing (#43)

Co-authored-by: davenportjw <jasondavenport@google.com>

Author: donmccasland

build/int.cloudbuild.yaml

@@ -20,7 +20,7 @@ steps:
   env:
   - 'TF_VAR_org_id=$_ORG_ID'
   - 'TF_VAR_folder_id=$_FOLDER_ID'
-  - 'TF_VAR_billing_account=$_BILLING_ACCOUNT'
+  - 'TF_VAR_billing_account=$_LR_BILLING_ACCOUNT'
 - id: create-dwh
   name: 'gcr.io/cloud-foundation-cicd/$_DOCKER_IMAGE_DEVELOPER_TOOLS:$_DOCKER_TAG_VERSION_DEVELOPER_TOOLS'
   args: ['/bin/bash', '-c', 'cft test run TestAnalyticsLakehouse --stage init --verbose']