[NEW CHECK] check dependabot

[mcm1957]

I'm sure that

• This issue does not report a false-positive detection (use dedicated template for this)
• This issue does not request a change or removal of existing check (use dedicated template for this)
• There is no other (open) issue with the same topic (use the search!)

Description of check to be added

If a dependabot setup exists perform the following checks:

If using 'monthly' suggest to use random crontab usage

Check if invalid elements exist, i.e
monthly does not support day
crontab does not suport day (--> should be fixed within PR)

Link to repository

https://github.com/patricknitsch/ioBroker.grohe-smarthome/tree/main

Checker version

5.2.2