Update Bazel container version to 0.18.0. (#204)

container/build.py

diff --git a/container/build.py b/container/build.py
index 8435b36..eb23b1f 100644
--- a/container/build.py
+++ b/container/build.py
@@ -80,7 +80,7 @@
 import subprocess
 import sys
 
-LATEST_BAZEL_VERSION = "0.17.2"
+LATEST_BAZEL_VERSION = "0.18.0"
 
 SUPPORTED_TYPES = [
     "rbe-debian8", "rbe-debian9", "rbe-ubuntu16_04", "ubuntu16_04-bazel",

container/common/bazel/version.bzl

diff --git a/container/common/bazel/version.bzl b/container/common/bazel/version.bzl
index 1744ab3..ef7a35a 100644
--- a/container/common/bazel/version.bzl
+++ b/container/common/bazel/version.bzl
@@ -5,4 +5,5 @@
     "0.16.1": "17ab70344645359fd4178002f367885e9019ae7507c9c1ade8220f3628383444",
     "0.17.1": "feedbe02c81142ed95ef8d380472f0a0d88e1b9a4b1fb6e21728701032b68e02",
     "0.17.2": "31fac8b2edcc6d95f1afb21725f604479eb440596e7fc7554fd47e293020ced9",
+    "0.18.0": "48ddaa9c9fef73dbe68517f274f09b33c3c8fdf3410638808b609f82b177d397",
 }