python_3.13: use Py_(Is)Initialize(d) instead of (Is)PyEval_InitThreads

See:
https://docs.python.org/3.9/c-api/init.html#c.PyEval_ThreadsInitialized

```
Returns a non-zero value if PyEval_InitThreads() has been called. This
function can be called without holding the GIL, and therefore can be
used to avoid calls to the locking API when running single-threaded.

Changed in version 3.7: The GIL is now initialized by Py_Initialize().

Deprecated since version 3.9, will be removed in version 3.11.
```

Author: ader1990

PyMI/PyMI.cpp

@@ -34,9 +34,9 @@ static PyModuleDef mimodule = {
 
 PyObject* _initmi(void)
 {
-    if (!PyEval_ThreadsInitialized())
+    if (!Py_IsInitialized())
     {
-        PyEval_InitThreads();
+        Py_Initialize();
     }
 
     PyDateTime_IMPORT;