Update CMakeLists.txt for CUDA

parallel_worlds_1/src/CMakeLists.txt

-cmake_minimum_required( VERSION 3.1 )
+cmake_minimum_required( VERSION 3.12 )
 project( parallel_worlds_1 )
 
 set( EXECUTABLE ${PROJECT_NAME} )
@@ -16,6 +16,9 @@ endif( UNIX )
 find_package( OpenCV REQUIRED )
 include_directories( ${OpenCV_INCLUDE_DIRS} )
 
+# THX: https://stackoverflow.com/questions/67641589/how-can-i-tell-cmake-3-9-i-want-to-use-nvidias-opencl-library
+find_package( CUDA )
+set(OpenCL_ROOT "${CUDA_TOOLKIT_ROOT_DIR}")
 find_package( OpenCL REQUIRED )
 
 include_directories( ${OpenCL_INCLUDE_DIRS} )