Builds of Plasma master

[David Edmundson]

Next week on the 28th of February we will begin the transition of
Plasma to KF6/Qt6.

This will involve a few days of master both failing to build and
potentially having conflicting files with Plasma5 with libraries
temporarily with the same sonames linking conflicting libraries and so
on. It would be surprising if something doesn't break during this
transition.

We suggest distros packaging 'master' builds of Plasma either transfer
to Plasma/5.27 branches or pause updates to users during this
transition period.

David