set concurrency policy for cronjobs to forbid

[imilchev]

When Cronjobs are crashing we don't want to keep creating new jobs every hour. We should set the concurrency policy to forbid to prevent that from happening https://kubernetes.io/docs/concepts/workloads/controllers/cron-jobs/#concurrency-policy

Forbid: The CronJob does not allow concurrent runs; if it is time for a new job run and the previous job run hasn't finished yet, the CronJob skips the new job run