It's already done by kaboutdata

CMakeLists.txt

 PROJECT(ksquares)
 
 cmake_minimum_required (VERSION 2.8.12 FATAL_ERROR)
-set (QT_MIN_VERSION "5.3.0")
-set (KF5_MIN_VERSION "5.15.0")
+set (QT_MIN_VERSION "5.7.0")
+set (KF5_MIN_VERSION "5.30.0")
 
-find_package(ECM 1.7.0 REQUIRED CONFIG)
+find_package(ECM ${KF5_MIN_VERSION} REQUIRED CONFIG)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${ECM_MODULE_PATH} ${ECM_KDE_MODULE_DIR})
 
 find_package(Qt5 ${QT_MIN_VERSION} REQUIRED NO_MODULE COMPONENTS Widgets)

src/main.cpp

@@ -45,8 +45,6 @@ int main(int argc, char **argv)
     QCommandLineParser parser;
     KAboutData::setApplicationData(about);
     KCrash::initialize();
-    parser.addVersionOption();
-    parser.addHelpOption();
     parser.addOption(QCommandLineOption(QStringList() <<  QStringLiteral("demo"), i18n("Run game in demo (autoplay) mode")));
 
     about.setupCommandLine(&parser);