Support for referenced valueFiles in multiple sources ArgoCD applications

[almereyda]

Problem Statement

When using the new ArgoCD multiple sources applications argoproj/argo-cd#10432, one can reference (ref: source1) one source within e.g. the valueFiles of another with a shorthand flag $source1/values.yaml.

This notation is currently not supported by Helm Secrets.

Proposed Solution

Helm Secrets also works in multiple sources applications, in so that I can do:

  sources:
    - repoURL: https://github.com/example/secrets
      targetRevision: main
      ref: source
    - helm:
        valueFiles:
        - $source/values.yaml
        - secrets+age-import-kubernetes://argocd/sops-age#key?$source/secrets.yaml
      repoURL: https://github.com/example/chart
      targetRevision: main
      path: ./

This would also help to work around the limitations expressed in https://github.com/jkroepke/helm-secrets/wiki/ArgoCD-Integration#external-chart-and-local-values

Would such behaviour be welcomed by the maintainers here?

Environment

N/A

Additional information

No response

Acceptance Criteria

No response

[jkroepke]

See #316

[almereyda]

🙈 Thanks.