Remove utest stuff in build

Seems we were using scalatest :/

Author: alexarchambault

project/Deps.scala

@@ -17,6 +17,5 @@ object Deps {
   def scalajsDom = setting("org.scala-js" %%% "scalajs-dom" % "1.1.0")
   def scalatags = setting("com.lihaoyi" %%% "scalatags" % "0.9.4")
   def scalaTest = "org.scalatest" %% "scalatest" % "3.2.9"
-  def utest = setting("com.lihaoyi" %%% "utest" % "0.6.6")
 
 }

project/Settings.scala

@@ -117,11 +117,6 @@ object Settings {
     name := "plotly-" + name.value
   }
 
-  lazy val utest = Seq(
-    libraryDependencies += Deps.utest.value % "test",
-    testFrameworks += new TestFramework("utest.runner.Framework")
-  )
-
   val gitLock = new Object
 
   def runCommand(cmd: Seq[String], dir: File): Unit = {