build(release): bump version to v0.6.0

[mmols]

Summary

Release PR for v0.6.0

Changes

Added

• "remove-host" now has a "force" attribute that allows users to recover from the loss of one or more hosts.
• Added support for new extensions in standard pgEdge Enterprise Postgres image, including pgedge_vectorizer, pg_tokenizer, vchord_bm25, pg_vectorize, pgmq, pg_cron, and pg_stat_monitor.

Fixed

• Added validation to the "get-join-options" endpoint to ensure incoming host IDs are unique within the cluster.

Checklist

• Tests added or updated (unit and/or e2e, as needed)
• Documentation updated (if needed)
• Issue is linked (branch name or URL in PR description)
• Changelog entry added for user-facing behavior changes
• Breaking changes (if any) are clearly called out in the PR description