Upgrade bazlets to latest stable-2.16 to build with 2.16.18 API

Change-Id: Ieea8e7e470c806c9e90c8077567ccb4807da333b

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 8ea9c8a..361ec38 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "9e23df10840ca3976431c842fdada58c7a51c6e3",
+    commit = "855968156ecd58d422218d6b5c9872805df9e9fc",
     #local_path = "/home/<user>/projects/bazlets"
 )