Upgrade bazlets to latest stable-2.16 to build with 2.16.15 API

Change-Id: Iebd2bd6a692e1932fc51e1de2370774713a3c728

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 4de5840..9843dcf 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "100fe2760d3a71a97cb1e04a4424e91f27e88f12",
+    commit = "59529f046a5cb855d9fe3ee87110d53305ec69b9",
     #local_path = "/home/<user>/projects/bazlets",
 )