https://scalacenter.github.io/scalafix/docs/rules/external-rules.html
project/scalafix.sbt
addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.12.1")
sbt shell
> scalafixEnable
> scalafixAll dependency:[email protected]:scalazfix:0.2.0
> scalafixEnable
> scalafixAll https://raw.githubusercontent.com/scalaz/scalazfix/master/rules/src/main/scala/scalaz/ScalazFix.scala