[logback-user] new version of logback-json-classic

I would love to use this change to JsonLayout to make it easier to add custom data: https://github.com/qos-ch/logback-contrib/commit/eedebdfa83f012d13a76cb06580.... It made it to master in November of 2014, but from what I can tell, no version of logback-json-classic has been released since then. Any chance I can help motivate releasing a new version? Thanks much. -DB