[repo] Pin Ubuntu to 22.04

[Kielek]

Workoaround for actions/runner-images#10636 (comment)
Same PR for contrib: open-telemetry/opentelemetry-dotnet-contrib#2425

Changes

[repo] Pin Ubuntu to 22.04

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• [ ] Unit tests added/updated
• [ ] Appropriate CHANGELOG.md files updated for non-trivial changes
• [ ] Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.40%. Comparing base (c94c422) to head (d643e70).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6036   +/-   ##
=======================================
  Coverage   86.40%   86.40%           
=======================================
  Files         257      257           
  Lines       11693    11693           
=======================================
  Hits        10103    10103           
  Misses       1590     1590