docs: add redlock-universal to distributed locks implementations

[alexpota]

Summary

Adds redlock-universal to the list of NodeJS distributed lock implementations in the distlock documentation.

About redlock-universal

• Repository: https://github.com/alexpota/redlock-universal
• npm: https://www.npmjs.com/package/redlock-universal
• License: MIT

Key Features

• Full Redlock algorithm implementation for distributed locking
• Native Valkey GLIDE support (in addition to node-redis and ioredis)
• Auto-extension API (using()) that prevents lock expiry during long operations
• Atomic batch lock acquisition for deadlock-free multi-resource locking
• TypeScript-first with exported types
• Zero runtime dependencies

Why Include

As the Valkey ecosystem grows, having a well-maintained distributed lock library with native GLIDE support benefits Valkey users migrating from Redis or building new applications.

Checklist

• Follows existing documentation format
• Links to active, maintained repository
• Library supports Valkey through official GLIDE client

[madolson]

Sure, thanks for the implementation!