cmake: fix argument for configure_package_config_file

CMakeLists.txt

@@ -51,7 +51,7 @@ include(CMakePackageConfigHelpers)
 configure_package_config_file(
   ${PROJECT_SOURCE_DIR}/cmake/config.cmake.in
   ${PROJECT_BINARY_DIR}/mtime-config.cmake
-  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake
+  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/mtime/cmake
   NO_SET_AND_CHECK_MACRO NO_CHECK_REQUIRED_COMPONENTS_MACRO
 )