Update scalafix plugin to 0.9.28

fixed #454

Author: mlachkar

project/plugins.sbt

@@ -9,6 +9,6 @@ addSbtPlugin("org.portable-scala"     % "sbt-scalajs-crossproject"      % crossV
 addSbtPlugin("org.scala-native"       % "sbt-scala-native"              % scalaNativeVersion)
 addSbtPlugin("org.portable-scala"     % "sbt-scala-native-crossproject" % crossVer)
 addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module"              % "2.3.0")
-addSbtPlugin("ch.epfl.scala"          % "sbt-scalafix"                  % "0.9.27")
+addSbtPlugin("ch.epfl.scala"          % "sbt-scalafix"                  % "0.9.28")
 addSbtPlugin("com.eed3si9n"           % "sbt-buildinfo"                 % "0.10.0")
 addSbtPlugin("ch.epfl.scala"          % "sbt-version-policy"            % "1.0.1")

scalafix/tests/src/test/scala/fix/ScalafixTests.scala

@@ -12,11 +12,12 @@
 
 package fix
 
+import org.scalatest.FunSuiteLike
 import scala.meta._
 import scalafix.v0._
 import scalafix.testkit._
 
-class ScalafixTests extends scalafix.testkit.SemanticRuleSuite {
+class ScalafixTests extends scalafix.testkit.AbstractSemanticRuleSuite with FunSuiteLike {
 
   val only: Option[String] =
     // Some("Playground") // << to run only one test: