[RELEASE] release opentelemetry-cpp 1.19.0

[marcalff]

Fixes #3229

Changes

Please provide a brief description of the changes here.

• Bump version number to 1.19.0
• Update CHANGELOG
• Enforce include-what-you-use

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	1b63dfa
🔍 Latest deploy log	https://app.netlify.com/sites/opentelemetry-cpp-api-docs/deploys/67909da2926b5000085a9986

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.78%. Comparing base (e216555) to head (1b63dfa).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3249      +/-   ##
==========================================
- Coverage   87.80%   87.78%   -0.01%     
==========================================
  Files         198      198              
  Lines        6324     6324              
==========================================
- Hits         5552     5551       -1     
- Misses        772      773       +1     

see 1 file with indirect coverage changes

[lalitb]

Please include #3236 in this release. If there are any further comments. I will resolve them before release.