Merge branch 'stable-3.1'

* stable-3.1:
  Fix bazlets using latest stable-3.1 to build with 3.1.5 API
  Upgrade bazlets to latest stable-3.1 to build with 3.1.5 API
  Upgrade bazlets to latest stable-3.0 to build with 3.0.9 API
  Upgrade bazlets to latest stable-2.16 to build with 2.16.19 API

Change-Id: I51988045ff073cf6349828906a52a8e3150738d7

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 3204330..828b66c 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "51c1fd2758fcc1b900a80d4ebb037bc373f85d39",
+    commit = "5c26af9e0374ede4cd67939be972adf6c4cda791",
     #local_path = "/home/<user>/projects/bazlets",
 )