Build.scala: hardcode maximum number of parallel tasks to 8

Author: smarter

project/Build.scala

@@ -54,6 +54,9 @@ object DottyBuild extends Build {
 
   override def settings: Seq[Setting[_]] = {
     super.settings ++ Seq(
+      concurrentRestrictions in Global := {
+        Tags.limitAll(8) :: Nil
+      },
       scalaVersion in Global := scalacVersion,
       version in Global := dottyVersion,
       organization in Global := dottyOrganization,