Update sbt-scalafmt to 2.4.6

Author: scala-steward

project/plugins.sbt

@@ -6,4 +6,4 @@ addSbtPlugin("com.eed3si9n"  % "sbt-buildinfo"       % "0.10.0")
 addSbtPlugin("com.github.sbt"  % "sbt-ci-release"      % "1.5.10")
 addSbtPlugin("com.lihaoyi"   % "scalatex-sbt-plugin" % "0.3.11")
 addSbtPlugin("org.scala-js"  % "sbt-scalajs"         % "1.5.1")
-addSbtPlugin("org.scalameta" % "sbt-scalafmt"        % "2.4.5")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt"        % "2.4.6")