At the moment there is no .scalafmt file and no sbt plugin to check the scala code. I do not see any alternatives (like scalastyle or scalafix) too.

An example of .scalafmt file: https://github.com/apache/spark/blob/master/dev/.scalafmt.conf
SBT plugin: https://scalameta.org/scalafmt/docs/installation.html#sbt

Checking the code style on each PR is a good practice that allows to simplify the maintenance.