Detect immutable field changes

[okozachenko1203]

Is it possible to add the information in the change list if the change is for immutable fields of the resource type.

I was able to get the change path in dyff output format.

spec.selector.matchLabels.component  (Deployment/default/memcached-memcached)
  ± value change
    - server
    + server-new

I can see the default helm diff template in the code base.

helm-diff/diff/constant.go

Lines 1 to 13 in 9d4d8e7

	package diff
	const defaultTemplateReport = `[
	{{- $global := . -}}
	{{- range $idx, $entry := . -}}
	{
	"api": "{{ $entry.API }}",
	"kind": "{{ $entry.Kind }}",
	"namespace": "{{ $entry.Namespace }}",
	"name": "{{ $entry.Name }}",
	"change": "{{ $entry.Change }}"
	}{{ if not (last $idx $global) }},{{ end }}
	{{- end }}]`

It would be good if we can render the change path (for instance, spec.selector.matchLabels.component) in the tpl.

[yxxhero]

@okozachenko1203 PR is welcome.