Upgrade bazlets to latest stable-2.16

As the previously used commit was locally verified but not the one
merged in after reviewing.

Change-Id: Ic3406ad5f14cf4c11152869a3b3812f44b96546c

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 0b27310..7670b65 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "620a4eb3bc0749301043fd6a69570b61b86e742e",
+    commit = "577450c73780560972f8a1a92c91410192ff7224",
     #local_path = "/home/<user>/projects/bazlets",
 )