How to change setting inside SBT command?

With the help from sbt mailing list, I was able to create a solution as follows:

def publishSnapshot = Command.command("publish-snapshot") { state =>
  val extracted = Project extract state
  import extracted._
  val eVersion = getOpt(version).get // getting current version
  runTask(publish in Compile,
    append(Seq(version := "newVersion"), state),
    true
  )
  state
}