skip objective test if onnxmltools version is lower than 1.3

Signed-off-by: Jan-Benedikt Jagusch <jan.jagusch@gmail.com>

tests/lightgbm/test_objective_functions.py

@@ -2,6 +2,7 @@
 from typing import Dict, List, Tuple
 
 import numpy as np
+import onnxmltools
 import pandas as pd
 from onnx import ModelProto
 from onnxconverter_common.data_types import DoubleTensorType, TensorType
@@ -64,7 +65,7 @@ def _assert_almost_equal(actual: np.array, desired: np.array, decimal: int=7, fr
         success_rel = success_abs / len(actual)
         assert success_rel >= frac, f"Only {success_abs} out of {len(actual)} rows are almost equal to {decimal} decimals."
 
-
+    @unittest.skipIf(tuple(int(ver) for ver in onnxmltools.__version__.split(".")) < (1, 3), "not supported in this library version")
     def test_objective(self):
         """
         Test if a LGBMRegressor a with certain objective (e.g. 'poisson') can be converted to ONNX