Update sbt-scalafix, scalafix-core to 0.10.4 (#558)

Author: scala-steward

project/plugins.sbt

@@ -3,5 +3,5 @@ addSbtPlugin("org.portable-scala"     % "sbt-scalajs-crossproject"      % "1.2.0
 addSbtPlugin("org.scala-native"       % "sbt-scala-native"              % "0.4.7")
 addSbtPlugin("org.portable-scala"     % "sbt-scala-native-crossproject" % "1.2.0")
 addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module"              % "3.0.1")
-addSbtPlugin("ch.epfl.scala"          % "sbt-scalafix"                  % "0.10.1")
+addSbtPlugin("ch.epfl.scala"          % "sbt-scalafix"                  % "0.10.4")
 addSbtPlugin("com.eed3si9n"           % "sbt-buildinfo"                 % "0.11.0")