Upgrade bazlets to latest stable-2.14 to build with 2.14.20 API

Change-Id: I961590ab8083ef4c091984c18d99b7ce567f9065
diff --git a/WORKSPACE b/WORKSPACE
index c91d597..1d73607 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "8d7664e169100e537340aed89345c3245cf12f22",
+    commit = "39310fb43f4eaaad2e338b3bcbf393a2f4e11293",
     #local_path = "/home/<user>/projects/bazlets",
 )