add to cmake

Former-commit-id: ac9253ea93607ad2e4d97c2e306124b31415d786

tutorial/CMakeLists.txt

@@ -79,3 +79,4 @@ add_subdirectory("609_Boolean")
 endif()
 add_subdirectory("701_Statistics")
 add_subdirectory("702_WindingNumber")
+add_subdirectory("703_Decimation")