Update kubernetes to 1.16.0-rc.2

Signed-off-by: Lantao Liu <lantaol@google.com>

vendor/github.com/json-iterator/go/any.go

@@ -312,6 +312,10 @@ func (codec *directAnyCodec) Decode(ptr unsafe.Pointer, iter *Iterator) {
 
 func (codec *directAnyCodec) Encode(ptr unsafe.Pointer, stream *Stream) {
 	any := *(*Any)(ptr)
+	if any == nil {
+		stream.WriteNil()
+		return
+	}
 	any.WriteTo(stream)
 }