Pin to cargo deny 0.16.1 to avoid MSRV issue

[Wumpf]

What

Causes our ci to fail because we're on an older Rust version than what is required by 0.16.2

I'm pretty sure this happened unintentionally, see:

• Bug: MSRV is defacto 1.81.0 while advertised as 1.70.0 EmbarkStudios/cargo-deny#720

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

• PR Build Summary
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[github-actions]

Latest documentation preview deployed successfully.

Result	Commit	Link
✅	cb1451c	https://landing-cwvxr4c7o-rerun.vercel.app/docs

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