fix: resolve cargo audit CI workflow error

[orbitalturtle]

• Cargo audit was failing because a number of dependencies needed to be upgraded, including Rust, bytes, tokio, and time.
• Because of the Rust upgrade:
  • The nix flake needed to be upgraded as well.
  • Cargo clippy enforces some new rules.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 7.36%. Comparing base (971f69f) to head (aef4d27).

Files with missing lines	Patch %	Lines
src/main.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           master    #255      +/-   ##
=========================================
+ Coverage    6.88%   7.36%   +0.48%     
=========================================
  Files           1       1              
  Lines         218     190      -28     
=========================================
- Hits           15      14       -1     
+ Misses        203     176      -27     

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[orbitalturtle]

Looks like cargo audit wants rust to be upgraded, which I'll add to this pr soon and then hopefully the CI will stop throwing errors :-)