CronBuilder accepting -1 as argument for UNIX

[barunhalderkolkata]

Cron cron = CronBuilder.cron(CronDefinitionBuilder.instanceDefinitionFor(UNIX))
                    .withDoM(always())
                    .withMonth(always())
                    .withDoW(always())
                    .withHour(on(-1))
                    .withMinute(on(5))
                    .instance();

This is creating cron object instead of throwing error like java.lang.IllegalArgumentException: Value -1 not in range [0, 23]

And this is failing eventually while trying to parse.

[jmrozanec]

@barunhalderkolkata thank you for reporting this! May we ask a PR with a test? Thanks!

[jmrozanec]

@barunhalderkolkata Fixed!