steps:
- name: 'gcr.io/cloud-builders/gcloud'
  args: ['app', 'deploy', '--no-promote', "--version=$(echo $TAG_NAME | sed 's/[.]/-/g')"]
timeout: '1600s'

ERROR: (gcloud.app.deploy) argument --version/-v: Bad value [$(echo 0.0.1a4 | sed 's/[.]/-/g')]: May only contain lowercase letters, digits, and hyphens. Must begin and end with a letter or digit. Must not exceed 63 characters.