Update definitions, exercise-compiler, ... to 0.6.4

Author: 47erbot

build.sbt

@@ -16,8 +16,8 @@ lazy val exercises = (project in file("."))
   .settings(name := "exercises-stdlib")
   .settings(
     libraryDependencies ++= Seq(
-      "org.scala-exercises"        %% "exercise-compiler"         % "0.6.3",
-      "org.scala-exercises"        %% "definitions"               % "0.6.3",
+      "org.scala-exercises"        %% "exercise-compiler"         % "0.6.4",
+      "org.scala-exercises"        %% "definitions"               % "0.6.4",
       "com.chuusai"                %% "shapeless"                 % "2.3.3",
       "org.scalatest"              %% "scalatest"                 % "3.2.1",
       "org.scalacheck"             %% "scalacheck"                % "1.14.3",

project/plugins.sbt

@@ -1,4 +1,4 @@
-addSbtPlugin("org.scala-exercises" % "sbt-exercise"             % "0.6.3")
+addSbtPlugin("org.scala-exercises" % "sbt-exercise"             % "0.6.4")
 addSbtPlugin("com.geirsson"        % "sbt-ci-release"           % "1.5.3")
 addSbtPlugin("org.scalameta"       % "sbt-mdoc"                 % "2.2.4")
 addSbtPlugin("org.scalameta"       % "sbt-scalafmt"             % "2.4.2")