This update for tumbler fixes the following issues:

tumbler was updated to version 4.16.1 (boo#1205210)

  * gst-thumbnailer: Add mime type check (gxo#xfce/tumbler#65)
  * desktop-thumbnailer: Guard against null path
  * Fix typo in gthread version (gxo#xfce/tumbler!14)

- Add Recommends: ffmpegthumbnailer