Forces onnx version to 1.16.1 (#106)

# Description

On Windows, the latest onnx version 1.16.2 causes Access Violation
errors with pytorch. To avoid the error, we force Isaac Lab to use onnx
version 1.16.1

## Type of change

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applicable. -->

- Bug fix (non-breaking change which fixes an issue)


## Checklist

- [x] I have run the [`pre-commit` checks](https://pre-commit.com/) with
`./isaaclab.sh --format`
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [x] I have updated the changelog and the corresponding version in the
extension's `config/extension.toml` file
- [ ] I have added my name to the `CONTRIBUTORS.md` or my name already
exists there

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source/extensions/omni.isaac.lab/setup.py

@@ -20,6 +20,7 @@ INSTALL_REQUIRES = [
     # generic
     "numpy<2",
     "torch==2.4.0",
+    "onnx==1.16.1",  # 1.16.2 throws access violation on Windows
     "prettytable==3.3.0",
     "tensordict",
     "toml",