Merge pull request #1698 from scalacenter/update/sbt-scalajs-1.21.0

Update sbt-scalajs, scalajs-library_2.13, ... to 1.21.0

Author: tgodzik

project/plugins.sbt

@@ -2,7 +2,7 @@ addSbtPlugin("io.spray" % "sbt-revolver" % "0.10.0")
 addSbtPlugin("org.playframework.twirl" % "sbt-twirl" % "2.0.9")
 addSbtPlugin("io.github.irundaia" % "sbt-sassify" % "1.5.2")
 addSbtPlugin("com.github.sbt" % "sbt-native-packager" % "1.11.7")
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.20.2")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.21.0")
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.3.2")
 addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.14.4")