Update sbt-scalajs, scalajs-compiler, ... to 1.20.1 in series/6.2.x

Author: argonaut-bot[bot]

project/plugins.sbt

@@ -6,7 +6,7 @@ addSbtPlugin("com.github.sbt" % "sbt-release" % "1.3.0")
 
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.4")
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.19.0")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.20.1")
 
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.3.2")