avoid using .Release.Namespace

[ooraini]

It's difficult to use any sort of post-render such as Kustomize when {{ .Release.Namespace }} is used inside cmds, args or scripts.

Usage of {{ .Release.Namespace }} can be replaced with:

    - name: NAMESPACE
      valueFrom:
        fieldRef:
          fieldPath: metadata.namespace

In addition to the chart templates, the cleanup command takes namespace as a flag. Which is not consistent with other command and forces the use of bash for substitution.