Add onnx-simplifier dependency.

pyproject.toml

@@ -4,7 +4,8 @@ description="Aidge interoperability framework with PyTorch."
 dependencies = [
     "numpy>=1.20",
     "onnx>=1.16.0",
-    "torch>=2.5.1"
+    "torch>=2.5.1",
+    onnx-simplifier
 ]
 
 requires-python = ">= 3.10"