doc: update contact info

Signed-off-by: Gabriel Schulhof <gabrielschulhof@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/38689


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Michael Dawson <midawson@redhat.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>