doc: move mikeal to Collaborator Emeriti list

Per conversation with Mikeal, moving to Collaborator Emeriti list.

Mikeal will remain active in Evangelism so you'll still see him around
the org.

PR-URL: https://github.com/nodejs/node/pull/20113


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Сковорода Никита Андреевич <chalkerx@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Myles Borins <myles.borins@gmail.com>