Use different Docker image for Cloud Build.
The old image isn't released reliably, which has caused some problems in the past (failing builds due to an old Bazel version).
#
# Then access the website in your browser via http://localhost:8000
-FROM gcr.io/cloud-builders/bazel
+FROM launcher.gcr.io/google/bazel
RUN apt-get update && \
apt-get -y install ruby ruby-dev build-essential python-pygments && \
