Feat: Expose post-renderer flag in the upgrade subcommand

[ruizink]

Fixes #195

[acaire]

Works perfectly for me with helm v3.1.2:

helm diff upgrade --allow-unreleased --post-renderer /tmp/kustomize redis stable/redis

and /tmp/kustomize as :

#!/bin/bash
cat <&0 > all.yaml
kustomize build . && rm all.yaml

and various yaml:

# kustomization.yaml
resources:
- all.yaml
patches:
- replicas.yaml

# replicas.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: redis-slave
spec:
  replicas: 200

[AntonioMeireles]

@databus23

Hi,

what's holding this specific feature from landing into a formal release ? is there anything the community could help in order to speed up things ;-) ?

thanks in advance!

[mumoshu]

LGTM. Thanks a lot for your contribution ☺️

[AntonioMeireles]

Thanks all for getting this in ! what a about a new version now to match stock helm's ;-)

All the best!