doc: add guide to maintaining npm
This is based on the guide found on their wiki
refs: https://github.com/npm/npm/wiki/CLI-Team-Process#submitting-the-new-latest-x-to-nodejs
/cc @nodejs/npm
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This is based on the guide found on their wiki
refs: https://github.com/npm/npm/wiki/CLI-Team-Process#submitting-the-new-latest-x-to-nodejs
/cc @nodejs/npm