[repo] Trigger builds when SDK is changed

[CodeBlanch]

Changes

• Trigger a build if the SDK is changed via global.json. This was done over on contrib recently: Bump dotnet-sdk from 9.0.100 to 9.0.101 opentelemetry-dotnet-contrib#2427 (comment)

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.39%. Comparing base (6100452) to head (bbce404).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6050   +/-   ##
=======================================
  Coverage   86.39%   86.39%           
=======================================
  Files         257      257           
  Lines       11690    11690           
=======================================
  Hits        10100    10100           
  Misses       1590     1590