Default `Pickler[java.io.File]` is broken

[kiritsuku]

It only contains the type information:

scala> import pickling.Defaults._, pickling.json._
import pickling.Defaults._
import pickling.json._

scala> val f = new java.io.File("/a/b")
f: java.io.File = /a/b

scala> f.pickle
res0: pickling.json.pickleFormat.PickleType =
JSONPickle({
  "$type": "java.io.File"
})

[eed3si9n]

Thanks for the report. This is a variation of #60/#296.