config validation doesn't allow valid cron expressions

[karmseveeratjisc]

e.g.
cron(5/10 * ? * * *)

cron(5 9-17 ? * * *)

fail but are perfectly acceptable to AWS

cron(5 5-6 ? * * *)

works - single digit '-' ranges are fine.

The regex used in the schema also allows invalid cron expressions:

cron(/ 5-6 ? * * *)

workaround is to switch off the validation but not ideal

configValidationMode: off