Update bazlets to latest revision on stable-2.15 to build with 2.15.7 API

Change-Id: I434425767ec9b346f682cdb12b9c129ec126cf00
diff --git a/WORKSPACE b/WORKSPACE
index 8529dad..e54e60f 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "714a32382ebd02919007d3514513af4395768d80",
+    commit = "f1d3eefb78029298afe119b0d8b2a43de2b510f6",
     #local_path = "/home/<user>/projects/bazlets",
 )