bpo-42519: Replace PyObject_MALLOC() with PyObject_Malloc() (GH-23587)

No longer use deprecated aliases to functions:

* Replace PyObject_MALLOC() with PyObject_Malloc()
* Replace PyObject_REALLOC() with PyObject_Realloc()
* Replace PyObject_FREE() with PyObject_Free()
* Replace PyObject_Del() with PyObject_Free()
* Replace PyObject_DEL() with PyObject_Free()
diff --git a/Modules/md5module.c b/Modules/md5module.c
index 9bd2bd1..1c401e8 100644
--- a/Modules/md5module.c
+++ b/Modules/md5module.c
@@ -342,7 +342,7 @@ static void
 MD5_dealloc(PyObject *ptr)
 {
     PyTypeObject *tp = Py_TYPE(ptr);
-    PyObject_Del(ptr);
+    PyObject_Free(ptr);
     Py_DECREF(tp);
 }