Update sbt-scalafix to 0.12.0 (#269)

Author: scala-steward

project/plugins.sbt

@@ -1,5 +1,5 @@
 addSbtPlugin("ch.epfl.scala"                     % "sbt-bloop"        % "1.5.13")
-addSbtPlugin("ch.epfl.scala"                     % "sbt-scalafix"     % "0.10.4")
+addSbtPlugin("ch.epfl.scala"                     % "sbt-scalafix"     % "0.12.0")
 addSbtPlugin("com.eed3si9n"                      % "sbt-buildinfo"    % "0.11.0")
 addSbtPlugin("com.github.sbt"                    % "sbt-ci-release"   % "1.5.12")
 addSbtPlugin("com.github.sbt"                    % "sbt-unidoc"       % "0.5.0")