helm: support of `timeZone` for CronJob

[a7i]

closes #1243

Stable in 1.27 - field is optional https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/#time-zones

Test:

helm template deschduler ./descheduler -f ./descheduler/values.yaml --set timeZone=Etc/UTC

...
# Source: descheduler/templates/cronjob.yaml
apiVersion: batch/v1
kind: CronJob
metadata:
  name: deschduler-descheduler
  namespace: default
  labels:
    app.kubernetes.io/name: descheduler
    helm.sh/chart: descheduler-0.28.0
    app.kubernetes.io/instance: deschduler
    app.kubernetes.io/version: "0.28.0"
    app.kubernetes.io/managed-by: Helm
spec:
  schedule: "*/2 * * * *"
  concurrencyPolicy: "Forbid"
  timeZone: Etc/UTC
  jobTemplate:
    spec:
...

[knelasevero]

/approve

[k8s-ci-robot]

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[JaneLiuL]

/lgtm

[a7i]

/retest