Use rbe_preconfig for RBE toolchain config (#958)

diff --git a/WORKSPACE.bazel b/WORKSPACE.bazel
index b6599a6..429da7f 100644
--- a/WORKSPACE.bazel
+++ b/WORKSPACE.bazel
@@ -37,18 +37,13 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
 http_archive(
-    name = "bazel_toolchains",
-    sha256 = "179ec02f809e86abf56356d8898c8bd74069f1bd7c56044050c2cd3d79d0e024",
-    strip_prefix = "bazel-toolchains-4.1.0",
-    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-toolchains/releases/download/4.1.0/bazel-toolchains-4.1.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-toolchains/releases/download/4.1.0/bazel-toolchains-4.1.0.tar.gz",
-    ],
+    name = "bazelci_rules",
+    sha256 = "eca21884e6f66a88c358e580fd67a6b148d30ab57b1680f62a96c00f9bc6a07e",
+    strip_prefix = "bazelci_rules-1.0.0",
+    url = "https://github.com/bazelbuild/continuous-integration/releases/download/rules-1.0.0/bazelci_rules-1.0.0.tar.gz",
 )
 
-load("@bazel_toolchains//rules:rbe_repo.bzl", "rbe_autoconfig")
-
-# Creates a default toolchain config for RBE.
-# Use this as is if you are using the rbe_ubuntu16_04 container,
-# otherwise refer to RBE docs.
-rbe_autoconfig(name = "buildkite_config")
+# To run with RBE on Bazel CI, uncomment the following lines.
+#
+# load("@bazelci_rules//:rbe_repo.bzl", "rbe_preconfig")
+# rbe_preconfig(name = "buildkite_config", toolchain = "ubuntu1604-bazel-java8")