change: bump onnx version to >=1.15.0 (#4514)

Author: benieric

requirements/extras/test_requirements.txt

@@ -31,7 +31,7 @@ transformers>=4.36.0
 sentencepiece==0.1.99
 # https://github.com/triton-inference-server/server/issues/6246
 tritonclient[http]<2.37.0
-onnx==1.14.1
+onnx>=1.15.0
 # tf2onnx==1.15.1
 nbformat>=5.9,<6
 accelerate>=0.24.1,<=0.27.0