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

Change-Id: I97c4967c0c6361e62cc7c2ff104c86b637a60dc7

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index ac87817..60d9408 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "d044cd60d37e302d9ac324f7a2c4e48b4011d4e6",
+    commit = "c2227415d5044f8439bd47edffb0f052f8da2ac5",
     # local_path = "/home/<user>/projects/bazlets",
 )