Upgrade bazlets to latest master to build with 3.1.1 API

Change-Id: Ib903dd44cdbbb31b61ef7b9ef9baca89629e6c80

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 37dd691..5fd9116 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "5f7ca2e226195c2de6eece2c160a9a7690dc7be8",
+    commit = "ee63e730eafc01baf316dc528c3a4e1046952434",
     #local_path = "/home/<user>/projects/bazlets",
 )