[Helm] registry login by json key

authenticate by "helm registry login"

helm registry login -u _json_key_base64 --password <base_64_key> \
   https://europe-north1-docker.pkg.dev/project-id/my-artifact-registry

authenticate by "config.json" file

Basically in the step where we want to push our *.tgz., we need to set the env HELM_REGISTRY_CONFIG equal to the default path of the docker config.json.

steps:
  - name: 'alpine/helm:3.9.1'
    id: 'helm package'
    args: ['package', '.']
  - name: 'alpine/helm:3.9.1'
    id: 'helm push'
    env:
      - 'HELM_REGISTRY_CONFIG=../builder/home/.docker/config.json'
    entrypoint: 'sh'
    args:
      - '-c'
      - |
        helm push --debug mylibchart-*.tgz oci://europe-west3-docker.pkg.dev/$PROJECT_ID/helm-registry