macOS - Build tips

[rubenvarela]

After step 6,

export CMAKE_PREFIX_PATH="/opt/homebrew/opt/qt@5/lib/cmake/"

Replace command on step 10 with,

/opt/homebrew/opt/qt@5/bin/macdeployqt rclone-browser.app -executable="rclone-browser.app/Contents/MacOS/rclone-browser" -qmldir=../src/