C+A: Add Lucio De Re

I entered only one of his several addresses, the one that recent CLs use.

R=rsc, lucio
CC=golang-dev
https://golang.org/cl/4368078

AUTHORS

@@ -84,6 +84,7 @@ Kevin Ballard <kevin@sb.org>
 Kyle Consalus <consalus@gmail.com>
 Kyle Lemons <kyle@kylelemons.net>
 Lorenzo Stoakes <lstoakes@gmail.com>
+Lucio De Re <lucio.dere@gmail.com>
 Luit van Drongelen <luitvd@gmail.com>
 Markus Duft <markus.duft@salomon.at>
 Martin Neubauer <m.ne@gmx.net>

CONTRIBUTORS

@@ -131,6 +131,7 @@ Kyle Consalus <consalus@gmail.com>
 Kyle Lemons <kyle@kylelemons.net> <etherealflaim@gmail.com>
 Larry Hosken <lahosken@golang.org>
 Lorenzo Stoakes <lstoakes@gmail.com>
+Lucio De Re <lucio.dere@gmail.com>
 Luit van Drongelen <luitvd@gmail.com>
 Luuk van Dijk <lvd@golang.org> <lvd@google.com>
 Mark Zavislak <zavislak@google.com>