Upgrade bazlets to latest master to build with 3.1.2 API

Change-Id: I19b77ea639422b07e88d9dfebceb5d3eb9be527e

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 2db4260..4c46a96 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "ee63e730eafc01baf316dc528c3a4e1046952434",
+    commit = "8c8df720486ebe0b60adccd0eceb1c8122edaf58",
     #local_path = "/home/<user>/projects/bazlets",
 )