Upgrade bazlets to latest stable-2.16 to build with 2.16.2 API

Change-Id: I2d6d8e7b70707995c64cd1bdbd16dde52fb9f257
diff --git a/WORKSPACE b/WORKSPACE
index 67abb70..2e3f62d 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "d025e909c2e8a369712165309f599a2765005f2d",
+    commit = "09a18a88ebdada986d32c1f50581e8734a47939a",
     #    local_path = "/Users/dpursehouse/git/bazlets",
 )