Log Message:
audio/fasttracker2: Update to 1.56

Changes since v1.55

v1.56 - 11.07.2022
- Fixed some possible issues with fullscreen in Linux (still buggy)
- Fixed some issues with restoring the window size and image stretch mode when
  loading or resetting the config when the program is running.
- Bugfix: Focus was lost when drag-n-dropping a file onto the tracker,
  which meant that the first following mouse click was ignored.
- Windows/macOS: Updated SDL from 2.0.20 to 2.0.22