Container: Add parameter to only schedule if it is a certain day

[MrSeccubus]

In order to do "First Monday of the month" type scheduling in Kubernetes I would like the scan command in a container to accept a third parameter that instructs the container to only run the scan if today is a Mon, Tue, , etc.

Rationel: Like corn, Kubernetes cronjobs interpret the schedule 0 1 1-7 * Mon cmd as run cmd at 01:00 on day 1 through 7 of the month AND every Monday.

Normally this get's fixed in cron as: 0 1 1-7 * * [ "$(date '+\%a')" == "Mon" ] && cmd, but that is hard to do in Kubernetes. So we need to incorportate the [ "$(date '+\%a')" == "Mon" ] && function into entrypoint.sh