Log Message:
graphics/gifski: update to 1.32.0

 - Added support for YUV4MPEG2 (Y4M), which is a primitive uncompressed video
   format that can be streamed from a command-line ffmpeg, without creating any
   temporary files on disk:

  ffmpeg -i "video.mp4" -f yuv4mpegpipe | gifski -o \ 
"crushed.gif" -

 - Added support for reading video from stdin. Specify - as the path.
 - Added warnings about reading or writing files from/to an interactive terminal.

There are no changes to the Windows GUI. Use previous MSI Windows installer.
The jump in version number is because I've previously accidentally tagged 1.13 \ 
as 1.31.