config.adoc: replace dead link

[thomas-mc-work]

The existing link leads to a placeholder site without content. I replaced it with something that seems to fit.

[quarkus-bot]

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[quarkus-bot]

Status for workflow Quarkus Documentation CI

This is the status report for running Quarkus Documentation CI on commit 1f23eb9.

✅ The latest workflow run for the pull request has completed successfully.

It should be safe to merge provided you have a look at the other checks in the summary.

[github-actions]

🙈 The PR is closed and the preview is expired.

[gsmet]

Thanks!