Update build.sc to current mill version

scratchip/assets/build.sc

@@ -1,20 +1,32 @@
 import mill._, scalalib._
-import ammonite.ops._
 import java.nio.file.Paths
 
 object chisel extends ScalaModule {
-  def scalaVersion = "2.12.6"
+  def scalaVersion = "2.13.8"
   def scalacOptions = Seq(
-    "-Xsource:2.11",
+    "-language:reflectiveCalls",
+    "-deprecation",
+    "-feature",
+    "-Xcheckinit",
+    "-P:chiselplugin:genBundleElements"
+  )
+
+  def millSourcePath = super.millSourcePath / os.up
+
+  override def ivyDeps = Agg(
+    ivy"edu.berkeley.cs::chisel3:3.5.1",
+  )
+
+  override def scalacPluginIvyDeps = Agg(
+    ivy"edu.berkeley.cs:::chisel3-plugin:3.5.1",
   )
-  def millSourcePath = super.millSourcePath / ammonite.ops.up
 
   def unmanagedClasspath = T {
     val lib_path = T.ctx.env.get("MILL_LIB") match {
-      case Some(lib) => Path(Paths.get(lib).toAbsolutePath)
+      case Some(lib) => os.Path(Paths.get(lib).toAbsolutePath)
       case None      => millSourcePath / "lib"
     }
-    if (!ammonite.ops.exists(lib_path)) Agg()
-    else Agg.from(ammonite.ops.ls(lib_path).map(PathRef(_)))
+    if (!os.exists(lib_path)) Agg()
+    else Agg.from(os.list(lib_path).map(PathRef(_)))
   }
-}
+}