Renovate config is not correctly read on v30

As reported originally here: renovatebot/renovate#13054

Copypaste from my comment here: renovatebot/renovate#13054 (comment):

I believe this could be related to:

config: Renovate will now fail if RENOVATE_CONFIG_FILE is specified without a file extension

(https://github.com/renovatebot/renovate/releases/tag/30.0.0)

This should have been fixed here: #170

But unfortunately the line introduced in that PR will not be evaluated because the whole env section is guarded by another if:

helm-charts/charts/renovate/templates/cronjob.yaml

Line 88 in 5e50b02

{{- if or .Values.redis.enabled .Values.renovate.existingConfigFile .Values.env .Values.dind.enabled }}

As a workaround, this can be specified in the values.yml
  env:
    RENOVATE_CONFIG_FILE: /usr/src/app/config.json

Actually, if I'm reading this correctly, specifying anything on env will cause #170 to behave as intended, so doing:

env:
  foo: bar

Should also be a valid workaround.