Merge pull request #396 from scala-steward/update/sbt-scalajs-1.15.0

Update sbt-scalajs, scalajs-compiler, ... to 1.15.0

Author: satabin

project/plugins.sbt

@@ -1,4 +1,4 @@
 addSbtPlugin("org.typelevel" % "sbt-typelevel" % "0.6.3")
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.14.0")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.15.0")
 addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.16")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.6")