Refactor ci with nix

[yanganto]

• CI will use MSRV from Rust manifest (Cargo.toml)
• Reduce usage of actions-rs, which are no longer maintained after Oct 13, 2023.
• Set up dependency upgrade bot
• Refactor lint, test, build with Nix
• Allow codecov upload failure

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.0%. Comparing base (c7b261d) to head (1cc6f51).
Report is 10 commits behind head on master.

❗ Current head 1cc6f51 differs from pull request most recent head c12841b

Please upload reports for the commit c12841b to get more accurate results.

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #25    +/-   ##
======================================
  Coverage     0.0%   0.0%            
======================================
  Files          17     17            
  Lines        3151   3031   -120     
======================================
+ Misses       3151   3031   -120     

Flag	Coverage Δ
rust	0.0% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dr-orlovsky]

can you please also remove dependabot from here?

[dr-orlovsky]

ACK c12841b