Changed an example of .jenkins

[kimitaka]

The URL to a Jenkins project must end with "/". If it doesn't, we can't open a console page correctly because Jenkins Status combine specified URL, a build number and "/console" like this.

opn(settings.url + status.buildNr.toString() + "/console");

I think this is not a bug, but an incorrect example of ".jenkins" file make new users confused. So I opened this pull request.

[alefragnani]

Hi @kimitaka ,

Good catch! It's really a bug/typo in README

Thank you