CBOR support

[davetapley]

• CBOR support #652

Draft for feedback. No tests yet, but it seems to work.

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.80%. Comparing base (8c9f4b0) to head (04f6542).
⚠️ Report is 30 commits behind head on main.

Files with missing lines	Patch %	Lines
serde/cbor.py	77.77%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #653      +/-   ##
==========================================
- Coverage   90.91%   90.80%   -0.12%     
==========================================
  Files          13       14       +1     
  Lines        2004     2022      +18     
  Branches      367      367              
==========================================
+ Hits         1822     1836      +14     
- Misses        123      127       +4     
  Partials       59       59              

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[davetapley]

Close for separate package per #652 (comment)