Update sbt-scalajs, scalajs-compiler, ... to 1.20.1 (#529)

Author: softwaremill-ci

project/plugins.sbt

@@ -1,5 +1,5 @@
 libraryDependencies += "org.scala-js" %% "scalajs-env-selenium" % "1.1.1"
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.19.0")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.20.1")
 addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.5.7")
 addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.11.0")