Adapt build system for building against qt6

CMakeLists.txt

@@ -50,7 +50,7 @@ set(LIBKLEO_LIB_VERSION "5.19.40")
 set(QT_REQUIRED_VERSION "5.15.2")
 set(KIMAP_LIB_VERSION "5.19.40")
 set(PIMCOMMON_LIB_VERSION "5.19.40")
-find_package(Qt5 ${QT_REQUIRED_VERSION} CONFIG REQUIRED Widgets WebEngine WebEngineWidgets)
+find_package(Qt${QT_MAJOR_VERSION} ${QT_REQUIRED_VERSION} CONFIG REQUIRED Widgets WebEngine WebEngineWidgets)
 
 # Find KF5 package
 find_package(KF5Crash ${KF5_MIN_VERSION} REQUIRED)

contactprintthemeeditor/CMakeLists.txt

@@ -34,7 +34,6 @@ if (COMPILE_WITH_UNITY_CMAKE_SUPPORT)
 endif()
 
 target_link_libraries(contactprintthemeeditor
-    Qt::WebEngineWidgets
     KF5::DBusAddons
     KF5::NewStuff
     KF5::AkonadiContact
@@ -42,7 +41,7 @@ target_link_libraries(contactprintthemeeditor
     grantleethemeeditor
     KF5::PimTextEdit
     KF5::I18n
-    Qt::WebEngineWidgets
+    Qt${QT_MAJOR_VERSION}::WebEngineWidgets
     KF5::Crash
     )