Merge branch 'stable-3.1'

* stable-3.1:
  Upgrade bazlets to latest stable-2.16 to build with 2.16.18 API
  Bump Bazel version to 3.1.0
  Bump Bazel version to 3.0.0

Change-Id: Ib4ed142a83217d6bc19b7cd720fabaf441a7bcba

WORKSPACE

diff --git a/WORKSPACE b/WORKSPACE
index 6318608..0edb345 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "cd715d269734e7bb0aa2fc4a01d2d2e279631cc7",
+    commit = "5c26af9e0374ede4cd67939be972adf6c4cda791",
     #local_path = "/home/<user>/projects/bazlets",
 )