Add Coverage Badges Extension to the managed set

[darinpope]

Add Coverage Badges Extension to the managed set

Testing done

• LINE=weekly PLUGINS=coverage-badges-extension bash local-test.sh
• LINE=2.479.x PLUGINS=coverage-badges-extension bash local-test.sh
• LINE=2.462.x PLUGINS=coverage-badges-extension bash local-test.sh
• LINE=2.452.x PLUGINS=coverage-badges-extension bash local-test.sh

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue

[darinpope]

Merging even with failures. All but ec were:

Could not transfer artifact ...xyz... from/to azure-aks-internal (http://artifact-caching-proxy.artifact-caching-proxy.svc.cluster.local:8080/): status code: 403, reason phrase: Forbidden (403)

ec2 was a flake for just one LINE.