fix: unpin cbindgen

[zachschuermann]

What changes are proposed in this pull request?

pretty quick response + release from cbindgen folks. now we can unpin and depend on known-good and above version (0.29.2).

resolves #1413

How was this change tested?

cargo c

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.67%. Comparing base (b78e080) to head (8613ad1).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1414      +/-   ##
==========================================
- Coverage   84.68%   84.67%   -0.02%     
==========================================
  Files         116      116              
  Lines       29762    29762              
  Branches    29762    29762              
==========================================
- Hits        25203    25200       -3     
- Misses       3343     3344       +1     
- Partials     1216     1218       +2     

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