Upgrade bazlets to latest stable-3.0 to build with 3.0.4 API

Change-Id: I4de05675ff66bf4bdc9fed1f5e75347e78ef7101

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 4c3b85d..b4b0030 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "2118fd30e24f339f5daf5310144dcb7a9123bc90",
+    commit = "ca31f016a3130c3eeb032538d2832bf555559b28",
     #local_path = "/home/<user>/projects/bazlets",
 )