lib/time: update tzdata to 2018i

Updates #22487

Change-Id: Iab4874ddef8e47eb99cd03e1c40af8372cce65c6
Reviewed-on: https://go-review.googlesource.com/c/156637
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

lib/time/update.bash

@@ -8,8 +8,8 @@
 # Consult https://www.iana.org/time-zones for the latest versions.
 
 # Versions to use.
-CODE=2018g
-DATA=2018g
+CODE=2018i
+DATA=2018i
 
 set -e
 rm -rf work