Merge branch 'stable-3.1'

* stable-3.1:
  Http: fix generation of the custom readonly message
  Upgrade bazlets to latest stable-2.16 to build with 2.16.18 API
  Bump Bazel version to 3.1.0

Change-Id: I9850c32ed9887a86a0f7ac95a39df8201ff5a8f5
diff --git a/WORKSPACE b/WORKSPACE
index 975f14e..38cb42b 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "fc1bfdf008c4b07e7cc4214fdacf25560276f9c4",
+    commit = "5c26af9e0374ede4cd67939be972adf6c4cda791",
     #local_path = "/home/<user>/projects/bazlets",
 )