Update sbt-scalafix, scalafix-core to 0.9.31

Author: scala-steward

project/plugins.sbt

@@ -1,7 +1,7 @@
 libraryDependencies += "org.scala-js" %% "scalajs-env-jsdom-nodejs" % "1.1.0"
 libraryDependencies += "org.scala-js" %% "scalajs-env-selenium"     % "1.1.1"
 
-addSbtPlugin("ch.epfl.scala" % "sbt-scalafix"        % "0.9.30")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix"        % "0.9.31")
 addSbtPlugin("com.eed3si9n"  % "sbt-buildinfo"       % "0.10.0")
 addSbtPlugin("com.geirsson"  % "sbt-ci-release"      % "1.5.7")
 addSbtPlugin("com.lihaoyi"   % "scalatex-sbt-plugin" % "0.3.11")