Allow "dummy" ticket ids in commiticketing

[sleicht]

I know that it goes against the original intent. But sometimes you simply don't have a ticket or are in a repository where the current ticket number doesn't make sense. For such cases, I sometimes use ticket numbers like TICKET-0000. This should also be allowed.
Sure, in the command line, the check can be temporarily disabled, but sometimes you're in a GUI or don't know the option right now.

[AFulgens]

Indeed, it kind of goes against the original intent of the hook. However, in case you are serious about the original intent, you would use cojira anyways, so I'm not 100% against relaxing the regex to allow [0-9]* instead of [1-9][0-9]*.