Update bazlets to latest revision on stable-2.15

Remove reference to deprecated FileType to fix the build with
the latest bazel version.

Change-Id: I1dec88d8bfca8e729d7711571d896d9cf47742b4
diff --git a/WORKSPACE b/WORKSPACE
index f041cc4..8e21074 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "f4fcc606a6afa8ce27a013bcf62e495a5ec2505c",
+    commit = "8386b3fbf80e375f0a10c8386c0a8dfe260c5c1b",
     #local_path = "/home/<user>/projects/bazlets",
 )