add Scala 3.0.0-RC1 to crossbuild

.travis.yml

@@ -47,6 +47,12 @@ jobs:
         - SCALA_VERSION=3.0.0-M3
         - TRAVIS_JDK=8
 
+    - name: "Run tests with Scala 3 and AdoptOpenJDK 8"
+      script: scripts/test-code.sh
+      env:
+        - SCALA_VERSION=3.0.0-RC1
+        - TRAVIS_JDK=8
+
     - stage: publish
       name: "Publish artifacts to Bintray"
       script: sbt +publish

build.sbt

@@ -123,7 +123,7 @@ lazy val commonSettings = Def.settings(
   ),
   headerLicense := Some(HeaderLicense.Custom(s"Copyright (C) 2009-2021 Lightbend Inc. <https://www.lightbend.com>")),
   scalaVersion := Dependencies.Scala212,
-  crossScalaVersions := Seq(Dependencies.Scala212, Dependencies.Scala213, Dependencies.Scala3),
+  crossScalaVersions := Seq(Dependencies.Scala212, Dependencies.Scala213) ++ Dependencies.Scala3,
   javacOptions in Compile ++= javacSettings,
   javacOptions in Test ++= javacSettings,
   javacOptions in (Compile, compile) ++= Seq("-target", "1.8"), // sbt #1785, avoids passing to javadoc

project/Dependencies.scala

@@ -2,5 +2,5 @@ object Dependencies {
   // scalaVersion needs to be kept in sync with travis-ci
   val Scala212 = "2.12.13"
   val Scala213 = "2.13.4"
-  val Scala3   = "3.0.0-M3"
+  val Scala3   = Seq("3.0.0-M3", "3.0.0-RC1")
 }

project/build.properties

@@ -1 +1 @@
-sbt.version=1.4.6
+sbt.version=1.4.7

project/plugins.sbt

@@ -15,12 +15,12 @@ addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.8.1")
 
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.6.0")
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.3.1")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.5.0")
 
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "1.0.0")
 
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.2")
 
 addSbtPlugin("com.dwijnand" % "sbt-dynver" % "4.1.1")
 
-addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.5.1")
+addSbtPlugin("ch.epfl.lamp" % "sbt-dotty" % "0.5.3")