[SEMANTIC CONVENTIONS] Upgrade to semantic conventions 1.29.0

[marcalff]

Changes

Please provide a brief description of the changes here.

• Upgrade to semantic conventions 1.29.0

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[netlify]

✅ Deploy Preview for opentelemetry-cpp-api-docs canceled.

Name	Link
🔨 Latest commit	e45fd97
🔍 Latest deploy log	https://app.netlify.com/sites/opentelemetry-cpp-api-docs/deploys/674e35c71ae9920008e79c35

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.84%. Comparing base (ac4bba7) to head (e45fd97).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3182      +/-   ##
==========================================
- Coverage   87.86%   87.84%   -0.01%     
==========================================
  Files         195      195              
  Lines        6151     6151              
==========================================
- Hits         5404     5403       -1     
- Misses        747      748       +1     

see 1 file with indirect coverage changes