Update sbt-scalajs, scalajs-compiler, ... to 1.21.0

Author: darkfrog26

project/plugins.sbt

@@ -4,7 +4,7 @@ addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.3.2")
 
 addSbtPlugin("org.portable-scala" % "sbt-scala-native-crossproject" % "1.3.2")
 
-addSbtPlugin("org.scala-js"% "sbt-scalajs" % "1.20.2")
+addSbtPlugin("org.scala-js"% "sbt-scalajs" % "1.21.0")
 
 addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.5.10")