Plasma master switches to Qt6

[Nicolas Fella]

Hi,

The master branch for Plasma repos will be made Qt6-only tomorrow,
28.02.2023.

There will be disruption because of this. While we aim for getting a
basic workspace running as soon as possible non-essential functionality
might be broken for a while.

Existing kdesrc-build setups will be switched to building Plasma from
the Plasma/5.27 branch to keep things building with Qt5. Make sure your
.kdesrc-buildrc contains "branch-group kf5-qt5".

You can build the Qt6/master version by specifying the "kf6-qt6" branch
group.

Cheers

Nico