translation file is missing
line 18:
https://github.com/ColinDuquesnoy/MellowPlayer/blob/master/app/mellowplayer.qrc#L18
calls for fr.qm, but that seems not generated (yet), just the fr.ts is available

build error:
/usr/lib/qt5/bin/rcc -name mellowplayer mellowplayer.qrc -o qrc_mellowplayer.cpp
RCC: Error in 'mellowplayer.qrc': Cannot find file 'translations/mellowplayer_fr.qm'
Makefile:578: recipe for target 'qrc_mellowplayer.cpp' failed
make[1]: *** [qrc_mellowplayer.cpp] Error 1
make[1]: *** Waiting for unfinished jobs....