Add Kyvos press release to Apache Ossie updates

[ki-kyvos]

Summary

• Add a kyvos author entry to docs/updates/.authors.yml, including the name, description, and GitHub organization avatar.
• Add docs/updates/posts/kyvos-joins-osi.md, an external-link update post pointing to Kyvos' press release announcing its participation in the Apache OSSIE ecosystem.

Test plan

• Run mkdocs serve locally and confirm the Kyvos card renders on /updates/.
• Confirm the same card renders in the homepage's "Latest Updates" section.
• Confirm the card links to the Kyvos press release and opens it in a new tab.