Update sbt-scalajs, scalajs-compiler, ... to 1.20.2

http4s-steward[bot] · http4s-steward[bot] · commit 1dd7bc09a34e · 2026-01-05T16:19:11.000Z
diff --git a/project/plugins.sbt b/project/plugins.sbt
@@ -1,6 +1,6 @@
 addSbtPlugin("org.http4s" % "sbt-http4s-org" % "2.0.1")
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.18.2")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.20.2")
 
 addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.17")
 
