Upgrade bazlets to latest master to build with 3.2.1 API

Change-Id: I5a84ab6f4684aebee82384fc5204ec89c1804d9f

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 0edb345..16f5352 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "5c26af9e0374ede4cd67939be972adf6c4cda791",
+    commit = "53cfe52b1b691040fd03dfe025c0a381df48c6ee",
     #local_path = "/home/<user>/projects/bazlets",
 )