Adapt build system for building against qt6

CMakeLists.txt

@@ -9,7 +9,7 @@ set (RELEASE_SERVICE_COMPACT_VERSION "${RELEASE_SERVICE_VERSION_MAJOR}${RELEASE_
 project(ksquares VERSION "0.6.${RELEASE_SERVICE_COMPACT_VERSION}")
 
 set (QT_MIN_VERSION "5.15.0")
-set (KF_MIN_VERSION "5.89.0")
+set (KF_MIN_VERSION "5.90.0")
 
 find_package(ECM ${KF5_MIN_VERSION} REQUIRED CONFIG)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${ECM_MODULE_PATH} )
@@ -24,7 +24,8 @@ include(ECMSetupVersion)
 include(ECMAddTests)
 include(FeatureSummary)
 
-find_package(Qt5 ${QT_MIN_VERSION} REQUIRED NO_MODULE COMPONENTS Widgets)
+find_package(Qt${QT_MAJOR_VERSION} ${QT_MIN_VERSION} REQUIRED NO_MODULE COMPONENTS Widgets)
+find_package(Qt${QT_MAJOR_VERSION}QuickWidgets ${REQUIRED_QT_VERSION} CONFIG)
 find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     Config
     ConfigWidgets