multimedia/qmmp-qt5: update to 1.7.4 release (+)

Changes since 1.7.3:

• added support for embedded cover art images in the mpris plugin;
• fixed build with ProjectM 4.0 or higher;
• fixed build with TagLib 2.0;
• fixed cmake warning;
• fixed filter list update;
• fixed proxy URL;
• using case insensitive search for ReplayGain tags in the ffmpeg plugin;
• updated Chinese Traditional translation;
• updated French translation.