Qt 6.0 released

Version 6.0 of the Qtinterface framework is available. "Qt 6.0 is a starting point forthe next generation of Qt. It is not yet as feature-complete as 5.15, butwe will fill the gaps within the months to come. We've done a lot ofimportant work in laying out the foundations of the next version ofQt. Many of those changes might not be immediately visible, but I firmlybelieve they will help keep Qt competitive in the years to come."Changes include moving to C++17, the completion of the Unicode transition,a move away from OpenGL to a new internal rendering interface, additional3D capabilities, and more.