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 (6c4b1ec) 87.78% compared to head (744ef6e) 87.82%.

Additional details and impacted files

@@                Coverage Diff                 @@
##           gz-transport13     #465      +/-   ##
==================================================
+ Coverage           87.78%   87.82%   +0.03%     
==================================================
  Files                  59       59              
  Lines                5699     5699              
==================================================
+ Hits                 5003     5005       +2     
+ Misses                696      694       -2     

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