CONTRIBUTORS: add Clément Chigot (company CLA)

Change-Id: Ia4c173c8d97540f56e4735eb491217301396633f
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/165458
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index f8e5765..1c197a7 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -35,6 +35,7 @@
 Cherry Zhang <cherryyz@google.com>
 Chris Manghane <cmang@golang.org>
 Christopher Wedgwood <cw@f00f.org>
+Clément Chigot <clement.chigot@atos.net>
 Dave Cheney <dave@cheney.net>
 David Daney <david.daney@cavium.com>
 Diego Novillo <dnovillo@google.com>