Update bazlets to latest revision on stable-2.14

- Use the 2.14.5.1 API
- Fix deprecation of set() constructor in latest bazel

Change-Id: I2799e4aa192aac09ba9afff74a5b74deee1b541f

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 7ea896f..48c623f 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "e15ad03897f040435d6c5e808b697b1125b964c1",
+    commit = "52381b8a7cd9a68f39fd11a53fe5f4b16897a6e0",
     # local_path = "/home/<user>/projects/bazlets",
 )