multimedia/plexmediaserver: Update to 1.31.0.6654

ChangeLog: https://forums.plex.tv/t/plex-media-server/30447/554

NEW:

 * Detect end credits markers for movies and episodes (Plex Pass required)
 * Allow using end credits markers to determine fully watched state for movies
   and episodes (Plex Pass required)
 * (Linux) Automatic library updates are now triggered by filesystem permissions
   and ownership changes

FIXES:

 * (DVR) Some audio or subtitle streams could fail to be captured on channels
   with multiple audio or subtitle services
 * (IntroDetection) Detection may timeout on very slow systems causing items
   to retry indefinitely
 * (Transcoder) Transcoding from AV1 could take a very long time to start when
   a GPU that did not support it was present

PR:		269541
Reported by:	b.shertenlieb@yahoo.com (maintainer)