Migrate to Artifact Registry

[glasnt]

Multiple flakytests (#263, #264) relate to Container Registry issues.

Container Registry is deprecated and shutting down, please use the auto migration tool to migrate to Artifact Registry. For more details see: https://cloud.google.com/artifact-registry/docs/transition/auto-migrate-gcr-ar

• Samples should create images in pkg.dev repos.
• Substitution values should differentiate between the the default $REPO_NAME and an Artifact Registry repo (probably _AR_REPO_NAME
• Some common cloud build step images may have been migrated to Artifact Registry under their gcr.io domain, should confirm if AR-hosted images exist.

[glasnt]

Cloud Build Step images current status

• gcr.io/google.com/cloudsdktool/cloud-sdk image is hosted in AR https://cloud.google.com/sdk/docs/downloads-docker (though not visible in public directory listing)

  • should replace references to gcr.io/cloud-builders/gcloud
  • needs to have an entrypoint https://cloud.google.com/build/docs/configuring-builds/create-basic-configuration#json

• gcr.io/cloud-builders/docker is hosted on AR (and updated often)