Add myself to list of AUTHORS/CONTRIBUTORS for Go.

R=rsc
https://golang.org/cl/154180
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 2ad4107..67ccabd 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -54,6 +54,7 @@
 Robert Griesemer <gri@golang.org>
 Russ Cox <rsc@golang.org>
 Scott Schwartz <scotts@golang.org>
+Sergio Luis O. B. Correia <sergio@larces.uece.br>
 Stephen Ma <stephenm@golang.org>
 Tom Szymanski <tgs@google.com>
 Vish Subramanian <vish@google.com>