added maven source plugin to generate sources artifact when packaging
added maven source plugin to generate sources artifact when packaging

fantasy86/jline2,scala/scala-jline,tkruse/jline2,DALDEI/jline2,msaxena2/jline2,kaulkie/jline2,renew-tgi/jline2,ctubbsii/jline2,cosmin/jline2,scala/scala-jline