Add changelog note for Polygraphy minimum

Document the ONNX AutoCast dependency floor update in the 0.47 bug fixes.

Signed-off-by: Gwena Cunha <gcunhasergio@nvidia.com>

Author: gcunhase

CHANGELOG.rst

@@ -41,6 +41,7 @@ Changelog
 
 - Update HuggingFace checkpoint export to use name-based tied-weight deduplication instead of the previous address-based approach. The address-based deduplication could incorrectly drop an untied weight that happened to share memory with a tied one, producing an incomplete checkpoint (observed as a false positive on MiniMax-M2.7).
 - Fix EAGLE-3 training with context parallelism (``--cp_size > 1`` in ``examples/speculative_decoding``), which failed to start on ``accelerate >= 1.13`` and then raised ``got mixed torch.Tensor and DTensor``.
+- Polygraphy minimum dependency upgraded to ``0.53.4`` to solve ONNX AutoCast failures when marking optional graph outputs.
 
 0.46 (2026-08-17)
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