chore: add module-swapper for INT tests (#68)

Author: apeabody

build/int.cloudbuild.yaml

@@ -14,6 +14,9 @@
 
 timeout: 3600s
 steps:
+- id: swap-module-refs
+  name: 'gcr.io/cloud-foundation-cicd/$_DOCKER_IMAGE_DEVELOPER_TOOLS:$_DOCKER_TAG_VERSION_DEVELOPER_TOOLS'
+  args: ['/bin/bash', '-c', 'source /usr/local/bin/task_helper_functions.sh && module-swapper']
 - id: prepare
   name: 'gcr.io/cloud-foundation-cicd/$_DOCKER_IMAGE_DEVELOPER_TOOLS:$_DOCKER_TAG_VERSION_DEVELOPER_TOOLS'
   args: ['/bin/bash', '-c', 'source /usr/local/bin/task_helper_functions.sh && prepare_environment']