go.talks: Update talk with my new twitter handle.

R=adg
CC=golang-dev
https://golang.org/cl/13686043
diff --git a/2013/bestpractices.slide b/2013/bestpractices.slide
index dec2ea5..94be133 100644
--- a/2013/bestpractices.slide
+++ b/2013/bestpractices.slide
@@ -2,7 +2,7 @@
 
 Francesc Campoy Flores
 Gopher at Google
-@campoy83
+@francesc
 http://campoy.cat/+
 
 http://golang.org