Use latest chrome and chrome driver in GitLab QA

qa/Dockerfile

 FROM ruby:2.3
 LABEL maintainer "Grzegorz Bizon <grzegorz@gitlab.com>"
-
-ENV CHROME_VERSION 59.0.3071.109-1
-ENV CHROME_DRIVER_VERSION 2.30
+ENV DEBIAN_FRONTEND noninteractive
 
 ##
 # Update APT sources and install some dependencies
@@ -15,22 +13,17 @@ RUN apt-get update && apt-get install -y wget git unzip xvfb
 #
 RUN curl -sS -L https://dl.google.com/linux/linux_signing_key.pub | apt-key add -
 RUN echo "deb [arch=amd64] http://dl.google.com/linux/chrome/deb/ stable main" > /etc/apt/sources.list.d/google.list
-RUN apt-get update -q && DEBIAN_FRONTEND=noninteractive apt-get install -y google-chrome-stable=$CHROME_VERSION
+RUN apt-get update -q && apt-get install -y google-chrome-stable && apt-get clean
 
 ##
 # Install chromedriver to make it work with Selenium
 #
-RUN wget -q https://chromedriver.storage.googleapis.com/$CHROME_DRIVER_VERSION/chromedriver_linux64.zip
+RUN wget -q https://chromedriver.storage.googleapis.com/$(wget -q -O - https://chromedriver.storage.googleapis.com/LATEST_RELEASE)/chromedriver_linux64.zip
 RUN unzip chromedriver_linux64.zip -d /usr/local/bin
 
-RUN apt-get clean
-
 WORKDIR /home/qa
-
 COPY ./Gemfile* ./
-
 RUN bundle install
-
 COPY ./ ./
 
 ENTRYPOINT ["bin/test"]