Upgrade bazlets to latest master to build with 3.1.2 API

Change-Id: I65990a7b62169292d43622efa6de65fca5030c01

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 5fd9116..f097872 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",
 )