Remove import-excluding Predef.conforms

As of Scala 2.11 Predef.conforms isn't implicit anymore (and it's
deprecated), so import-excluding doesn't avoid the implicit (the
implicit version is now Predef.$conforms). Also in Scala 2.13
Predef.conforms has been removed.

main-actions/src/main/scala/sbt/Package.scala

@@ -7,7 +7,6 @@
 
 package sbt
 
-import scala.Predef.{ conforms => _, _ }
 import java.io.File
 import java.util.jar.{ Attributes, Manifest }
 import scala.collection.JavaConverters._

main-actions/src/main/scala/sbt/RawCompileLike.scala

@@ -11,7 +11,6 @@ import scala.annotation.tailrec
 import java.io.File
 import sbt.internal.inc.{ RawCompiler, ScalaInstance }
 
-import Predef.{ conforms => _, _ }
 import sbt.io.syntax._
 import sbt.io.IO