audio/flacon: the port had been updated to version 11.1.0

Since version 10.0.0 the program does not use external utilities
to calculate Replay Gain, the built-in method is used instead.
This accelerated the conversion process and reduced the number
of dependencies (particularly, metaflac, mp3gain, vorbisgain,
and wvgain are no longer needed).

Reported by: portscout