Upgrade bazlets to latest stable-3.1 to build with 3.1.6 API

Change-Id: I71ff74332dc9c6edffa0889c57f4ee4d19614181

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 36d460b..457f04b 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "fbe2b2fd07c95d752dced6b8624c9d5a08e8c6c6",
+    commit = "69ae6ee516ec1cc51d0a07fe4419a325eb9063ce",
     #local_path = "/home/<user>/projects/bazlets",
 )