Upgrade bazlets to latest master revision

Includes the following fix relevant to this project:

4d6d3a6 - Use now mandatory https protocol for MAVEN_CENTRAL

Bug: Issue 12170
Change-Id: Ib9dc690f7f444e8d521b477e559964a83060b09a

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 883ec60..4c16a90 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -28,7 +28,7 @@
 load("//tools:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "bf900bbe58f7a7802799d6d6477567b05ab2f399",
+    commit = "fbe2b2fd07c95d752dced6b8624c9d5a08e8c6c6",
     # local_path = "/home/<user>/projects/bazlets",
 )