Upgrade bazlets to latest master to build with 3.1.0-rc3 API

Change-Id: Ia04130a397940f04ea2379642dbf8aa7c47e3eef

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 41c4eaf..18afd76 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "cf5be217dc024c5e1a001ff24441bef7ac2d90d0",
+    commit = "3c5c68992ede5e2b6722abf4da03b034b57c8e89",
     #local_path = "/home/<user>/projects/bazlets",
 )