Fix run.py

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

benchmark/run.py

@@ -119,6 +119,10 @@ elif args.format == 'onnx':
     if not os.path.exists(onnx_path):
         onnx_path = op.save_model(format='onnx')
 
+    sess = onnxruntime.InferenceSession(onnx_path,
+                                        providers=onnxruntime.get_available_providers())
+
+
     @towhee.register
     def run_onnx(img):
         img = img.convert('RGB')