update CMakeLists.txt

CMakeLists.txt

 project(matplotlibcpp17)
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.12)
 
-find_package(PythonLibs 3 REQUIRED)
-find_package(PythonInterp 3 REQUIRED)
+find_package(Python3 COMPONENTS Interpreter Development)
 find_package(pybind11 REQUIRED)
 
 if(NOT DEFINED ADD_DEMO)
@@ -17,8 +16,8 @@ set(matplotlibcpp17_INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/include")
 
 function(add_demo name path)
   add_executable(${name} ${path})
-  target_include_directories(${name} PUBLIC ${pybind11_INCLUDE_DIR} ${PYTHON_INCLUDE_DIRS} ${matplotlibcpp17_INCLUDE_DIRS})
-  target_link_libraries(${name} ${PYTHON_LIBRARY} pybind11::embed)
+  target_include_directories(${name} PUBLIC ${pybind11_INCLUDE_DIR} ${Python3_INCLUDE_DIRS} ${matplotlibcpp17_INCLUDE_DIRS})
+  target_link_libraries(${name} ${Python3_LIBRARIES} pybind11::embed)
 endfunction()
 
 if(${ADD_DEMO})