fix(opentelemetry-semantic-conventions): update trace semantic conventions url

[jorgeepc]

Which problem is this PR solving?

This PR fixes the OpenTelemetry Semantic Conventions URL used in the readme file of the opentelemetry-semantic-conventions package. In the last release (v1.21.0) of the Opentelemetry Specification the Semantic Conventions section was moved to a separate repository.

Fixes # (issue)

Short description of the changes

Fix URL in readme file.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• Validate link navigation in readme

Checklist:

• Followed the style guidelines of this project
• Documentation has been updated

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: jorgeepc / name: Jorge Padilla (c9fc12b)

[pichlermarc]

Thanks 🙂

[codecov]

Codecov Report

Merging #3843 (20538a7) into main (2fb1b30) will decrease coverage by 1.80%.
The diff coverage is n/a.

❗ Current head 20538a7 differs from pull request most recent head c9fc12b. Consider uploading reports for the commit c9fc12b to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3843      +/-   ##
==========================================
- Coverage   92.95%   91.16%   -1.80%     
==========================================
  Files         297       82     -215     
  Lines        9060     1800    -7260     
  Branches     1848      363    -1485     
==========================================
- Hits         8422     1641    -6781     
+ Misses        638      159     -479     

see 221 files with indirect coverage changes