Add onnx to InputType enum (#18310)

Add onnx to `InputType` enum.

Signed-off-by: Tim Gymnich <tim@gymni.ch>

compiler/bindings/python/iree/compiler/tools/core.py

diff --git a/compiler/bindings/python/iree/compiler/tools/core.py b/compiler/bindings/python/iree/compiler/tools/core.py
index 19ec146..30732f5 100644
--- a/compiler/bindings/python/iree/compiler/tools/core.py
+++ b/compiler/bindings/python/iree/compiler/tools/core.py
@@ -48,6 +48,7 @@
     TOSA = "tosa"
     TM_TENSOR = "tm_tensor"
     TORCH = "torch"
+    ONNX = "onnx"
 
     @staticmethod
     def parse(spec: Union[str, InputType]) -> InputType: