Only compile sbt-launcher module in 2.11

So that we don't have to wait on its dependencies to add preliminary
support for scala 2.13

build.sbt

@@ -194,11 +194,17 @@ lazy val `sbt-launcher` = project
   .settings(
     shared,
     generatePack,
-    libs ++= Seq(
+    dontPublishIn("2.10", "2.12"),
+    libs ++= {
+      if (scalaBinaryVersion.value == "2.11")
+        Seq(
           Deps.caseApp,
           Deps.sbtLauncherInterface,
           Deps.typesafeConfig
         )
+      else
+        Nil
+    }
   )
 
 lazy val `http-server` = project