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

Change-Id: Ied6716126ea048c4cd9d91f48958cc4767cb3c14

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 34fd3fc..83ec8ab 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",
 )