Update CI badges in README

[iche033]

🦟 Bug fix

Summary

focal -> jammy
ign -> gz

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (6460f7c) 94.16% compared to head (cd4931b) 94.16%.

Additional details and impacted files

@@            Coverage Diff            @@
##           gz-math7     #571   +/-   ##
=========================================
  Coverage     94.16%   94.16%           
=========================================
  Files           145      145           
  Lines          9774     9774           
=========================================
  Hits           9204     9204           
  Misses          570      570           

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