remove unused import

Author: dontgitit

zio-http/shared/src/main/scala/zio/http/Header.scala

@@ -23,7 +23,6 @@ import java.util.Base64
 import java.util.concurrent.ConcurrentHashMap
 
 import scala.annotation.tailrec
-import scala.collection.compat.immutable.ArraySeq
 import scala.collection.mutable
 import scala.runtime.AbstractFunction11
 import scala.util.control.NonFatal