For qt6 we need kf5.90

Sync QT_MIN_VERSION with KF's REQUIRED_QT_VERSION

In KF we already looking for 5.15.2
and looking something lower than that
is a bit meaningless

CMakeLists.txt

@@ -8,8 +8,8 @@ cmake_minimum_required(VERSION 3.10.0 FATAL_ERROR)
 
 project(kolourpaint VERSION ${RELEASE_SERVICE_VERSION})
 
-set(QT_MIN_VERSION "5.11.0")
-set(KF5_MIN_VERSION "5.87.0")
+set(QT_MIN_VERSION "5.15.2")
+set(KF5_MIN_VERSION "5.90.0")
 set(KDE_COMPILERSETTINGS_LEVEL "5.84.0")
 
 find_package(ECM ${KF5_MIN_VERSION} REQUIRED NO_MODULE)