Fix Py_DECREF memory leak

Author: John-194

setup.py

@@ -51,7 +51,6 @@ def initialize_options(self):
         depends=depends,
         py_limited_api=True,
         define_macros=[
-            ('Py_LIMITED_API', '0x03020000'),
             ('NPY_NO_DEPRECATED_API', 'NPY_1_7_API_VERSION'),
             # ('DBSCAN_VERSION', json.dumps(version)),
         ]

src/dbscanmodule.cpp

@@ -71,8 +71,12 @@ static PyObject* DBSCAN_py(PyObject* self, PyObject* args, PyObject *kwargs)
     );
 
     parlay::internal::stop_scheduler();
-
-    return PyTuple_Pack(2, labels, core_samples);
+    
+    PyObject* result_tuple = PyTuple_Pack(2, labels, core_samples);
+    Py_DECREF(X);
+    Py_DECREF(core_samples);
+    Py_DECREF(labels);
+    return result_tuple;
 }
 
 PyDoc_STRVAR(doc_DBSCAN,