Use FindPython3 when cmake version >= 3.15.0

Signed-off-by: okhowang(王沛文) <okhowang@tencent.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c84194c..1f675c1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -51,18 +51,29 @@
                          "${WARNING_BORDER}")
 
 # Python 3 is only needed here to check for configuration warnings.
-find_package(PythonInterp 3)
-if(PYTHONINTERP_FOUND)
+if(NOT CMAKE_VERSION VERSION_LESS 3.15.0)
+    set(Python3_FIND_STRATEGY LOCATION)
+    find_package(Python3 COMPONENTS Interpreter)
+    if(Python3_Interpreter_FOUND)
+        set(MBEDTLS_PYTHON_EXECUTABLE ${Python3_EXECUTABLE})
+    endif()
+else()
+    find_package(PythonInterp 3)
+    if(PYTHONINTERP_FOUND)
+        set(MBEDTLS_PYTHON_EXECUTABLE ${PYTHON_EXECUTABLE})
+    endif()
+endif()
+if(MBEDTLS_PYTHON_EXECUTABLE)
 
     # If 128-bit keys are configured for CTR_DRBG, display an appropriate warning
-    execute_process(COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/config.py -f ${CMAKE_CURRENT_SOURCE_DIR}/include/mbedtls/config.h get MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
+    execute_process(COMMAND ${MBEDTLS_PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/config.py -f ${CMAKE_CURRENT_SOURCE_DIR}/include/mbedtls/config.h get MBEDTLS_CTR_DRBG_USE_128_BIT_KEY
                         RESULT_VARIABLE result)
     if(${result} EQUAL 0)
         message(WARNING ${CTR_DRBG_128_BIT_KEY_WARNING})
     endif()
 
     # If NULL Entropy is configured, display an appropriate warning
-    execute_process(COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/config.py -f ${CMAKE_CURRENT_SOURCE_DIR}/include/mbedtls/config.h get MBEDTLS_TEST_NULL_ENTROPY
+    execute_process(COMMAND ${MBEDTLS_PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/config.py -f ${CMAKE_CURRENT_SOURCE_DIR}/include/mbedtls/config.h get MBEDTLS_TEST_NULL_ENTROPY
                         RESULT_VARIABLE result)
     if(${result} EQUAL 0)
         message(WARNING ${NULL_ENTROPY_WARNING})