deprecating the npm public roadmap

The npm Public Roadmap is being deprecated in favor of using the GitHub Public Roadmap to track feature launches for the npm Registry, CLI, and website.

Launched in October of 2020, the original npm roadmap process worked well for the team. As time has passed, the benefits of using a shared roadmap for GitHub and npm now outweigh the flexibility of managing separate ones. From now on, all large launches will be tracked via the GitHub Public Roadmap.