Use AirSpec for property tests

msgpack-core/src/test/scala/org/msgpack/core/MessagePackSpec.scala

@@ -24,12 +24,14 @@ import xerial.core.util.{TimeReport, Timer}
 
 import scala.language.implicitConversions
 
+object MessagePackSpec {
+  def toHex(arr: Array[Byte]) = arr.map(x => f"$x%02x").mkString(" ")
+}
+
 trait MessagePackSpec extends AnyWordSpec with Matchers with GivenWhenThen with OptionValues with BeforeAndAfter with Benchmark with Logger {
 
   implicit def toTag(s: String): Tag = Tag(s)
 
-  def toHex(arr: Array[Byte]) = arr.map(x => f"$x%02x").mkString(" ")
-
   def createMessagePackData(f: MessagePacker => Unit): Array[Byte] = {
     val b      = new ByteArrayOutputStream()
     val packer = MessagePack.newDefaultPacker(b)