Merge pull request #48 from scala-steward/update/sbt-scalajs-0.6.31

Update sbt-scalajs, scalajs-library, ... to 0.6.31

Author: Atry

project/plugins.sbt

@@ -2,6 +2,6 @@ addSbtPlugin("com.thoughtworks.sbt-best-practice" % "sbt-best-practice" % "2.6.1
 
 addSbtPlugin("com.thoughtworks.sbt-scala-js-map" % "sbt-scala-js-map" % "2.0.0")
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.30")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.31")
 
 addSbtPlugin("com.thoughtworks.example" % "sbt-example" % "2.0.4")