Upgrade bazlets to latest master to build with 3.2.1 API

Change-Id: I5baa9612df5d1d33d2711c400928a21a227c45d8

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index b1a0bd5..3d93f07 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "81e56222d9cec5fc46b9a60d1948833406afda56",
+    commit = "53cfe52b1b691040fd03dfe025c0a381df48c6ee",
     #local_path = "/home/<user>/projects/bazlets",
 )