Fix build with CMP0048 set to NEW

CMakeLists.txt

@@ -1,6 +1,7 @@
 cmake_minimum_required(VERSION 3.0)
 
-project(KItemModels)
+set(KF5_VERSION "5.30.0") # handled by release scripts
+project(KItemModels VERSION ${KF5_VERSION})
 
 include(FeatureSummary)
 find_package(ECM 5.29.0  NO_MODULE)
@@ -23,9 +24,7 @@ include(GenerateExportHeader)
 include(ECMSetupVersion)
 include(ECMGenerateHeaders)
 
-set(KF5_VERSION "5.30.0") # handled by release scripts
-
-ecm_setup_version(${KF5_VERSION} VARIABLE_PREFIX KITEMMODELS
+ecm_setup_version(PROJECT VARIABLE_PREFIX KITEMMODELS
                         VERSION_HEADER "${CMAKE_CURRENT_BINARY_DIR}/kitemmodels_version.h"
                         PACKAGE_VERSION_FILE "${CMAKE_CURRENT_BINARY_DIR}/KF5ItemModelsConfigVersion.cmake"
                         SOVERSION 5)