Add support for postRenderers: in wrapped packages

Feature Request

Why

At the moment, modifying the spec of a git repo for a wrapped package is not possible with something like the example below since postRenderers: are not yet supported in wrapped packages leaving this to be a manual task.

packages:
  podinfo:
    enabled: true
    git:
      repo: https://my.git.repo.com/podinfo/podinfo.git
      branch: dev
      path: path/to/podinfo
    postRenderers:
      - kustomize:
        patchesStrategicMerge:
        - kind: GitRepository
          apiVersion: source.toolkit.fluxcd.io/v1
          metadata:
            name: podinfo
            namespace: podinfo
          spec:
            secretRef:
              name: private-git

Proposed Solution

Update the helpers template of the wrapper package to add support as suggested here.