add a 'dry run' mode

3 jobs for master in 4 minutes and 58 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed test-sbt #70485
mbr

00:02:21

 
  Build
passed assembly-sbt #70486
mbr

00:02:08

 
  Publish
passed build-latest-image #70487
mbr

00:00:29