Examples use rather old versions in the module imports

The examples import statements use rather old module versions.

for example: 

import QtQuick 2.8

Maybe upgrade should be done for the next release and choose at least either the minimum supported TESTED Qt version (now Qt 5.12, maybe Qt 5.15 in the next release) or the latest (maybe Qt 6.0 or Qt 6.1). 

Do not know what complications there might be for supporting both Qt 5 and Qt 6 at the same time.