Add scripted scala3-sandwich-sjs

sbt/src/sbt-test/project/scala3-sandwich-sjs/app/src/main/scala/app/Main.scala

@@ -0,0 +1,9 @@
+package app
+
+import mylib._
+
+object Main {
+  def main(args: Array[String]): Unit = {
+    println(MyLib.square(5))
+  }
+}

sbt/src/sbt-test/project/scala3-sandwich-sjs/build.sbt

@@ -0,0 +1,15 @@
+ThisBuild / scalaVersion := "2.13.4"
+ThisBuild / scalacOptions += "-Ytasty-reader"
+
+lazy val scala3code = project
+  .enablePlugins(ScalaJSPlugin)
+  .settings(scalaVersion := "3.0.0-M1")
+
+lazy val app = project
+  .enablePlugins(ScalaJSPlugin)
+  .dependsOn(scala3code)
+  .settings(
+    scalaVersion := "2.13.4",
+    scalacOptions += "-Ytasty-reader",
+    scalaJSUseMainModuleInitializer := true
+  )

sbt/src/sbt-test/project/scala3-sandwich-sjs/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.3.1")

sbt/src/sbt-test/project/scala3-sandwich-sjs/scala3code/src/main/scala/mylib/MyLib.scala

@@ -0,0 +1,5 @@
+package mylib
+
+object MyLib {
+  def square(x: Int): Int = x * x
+}

sbt/src/sbt-test/project/scala3-sandwich-sjs/test

@@ -0,0 +1 @@
+> app/run