Log Message:
mkvtoolnix: updated to 83.0

Version 83.0 "Circle Of Friends" 2024-03-10

New features and enhancements

* translations: added a Belarusian translation of the programs & the man pages
  by prydespar (see `AUTHORS`).
* mkvmerge, MKVToolNix GUI's chapter editor: added support for reading
  chapters from ffmpeg metadata files.
* MKVToolNix GUI: added a new action type for execution after jobs or the
  queue finishes: quitting MKVToolNix.

Build system changes

* The bundled `fmt` library was updated to v10.2.1.

Other changes

* Tons of changes were made to support the latest development versions of
  libEBML & libMatroska.