docs: update gpg key for Myles Borins

Original key did not have personal information associated with it.

The new key rectifies this problem

PR-URL: https://github.com/nodejs/node/pull/4657


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: James M Snell <jasnell@gmail.com>