doc,meta: update email addresses for misterdjules

Julien Gilli appears twice with two email addresses in the current
AUTHORS file. Use .mailmap to map one to the other (keeping the most
recent one). Also update email in the README from a (I believe invalid,
since it is not listed in the email repo aliases.json file) nodejs.org
email to the email they more recently committed with. Finally, re-run
`update-authors.js` so they only have one entry in AUTHORS.

PR-URL: https://github.com/nodejs/node/pull/39433


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>