Bump rustix in /bench in the cargo group across 1 directory (#537)

Bumps the cargo group with 1 update in the /bench directory: [rustix](https://github.com/bytecodealliance/rustix).


Updates `rustix` from 0.38.3 to 0.38.8
- [Release notes](https://github.com/bytecodealliance/rustix/releases)
- [Changelog](https://github.com/bytecodealliance/rustix/blob/main/CHANGES.md)
- [Commits](bytecodealliance/rustix@v0.38.3...v0.38.8)

---
updated-dependencies:
- dependency-name: rustix
  dependency-version: 0.38.8
  dependency-type: indirect
  dependency-group: cargo
...

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