Replace deprecated qt_add_translation function

[QuentiumYT]

Hello, the qt_add_translation is deprecated (as per https://doc.qt.io/qt-6/qtlinguist-cmake-qt-add-translation.html)

Also while trying to package your app, I struggled with set(copyq_DEFINITIONS ${${copyq_qt}Widgets_DEFINITIONS}). It seems to look for extra widgets definitions but launchpad didn't work. Looks fine without it so I'm wondering if it's still needed.

Thanks for your reply :)

[QuentiumYT]

Oh yes Qt5 doesn't support it, would you like me to add a fallback?

if("${QT_VERSION_MAJOR}" STREQUAL "5")
  qt5_add_translation(copyq_QM ${copyq_TRANSLATIONS})
else()
  qt6_add_translations(copyq-common TS_FILES ${${PROJECT_NAME}_translations} QM_FILES_OUTPUT_VARIABLE copyq_QM)
endif()