gitlab-ci for building and then using a container using podman

.gitlab-ci.yml

stages:
  - build-image
  - mirror

before_script:
  - podman login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
  - podman pull $IMAGE_TAG || true  # ensure the latest is downloaded

variables:
  IMAGE_TAG: $CI_REGISTRY_IMAGE:latest

build-image:
  image: quay.io/podman/stable
  stage: build-image
  script:
    - podman build --cache-from $IMAGE_TAG --pull -t $IMAGE_TAG . 
    - podman push $IMAGE_TAG

mirror-nightly:
  image: $IMAGE_TAG
  stage: mirror
  script:
    - echo "hello, world!"