update chrome version and chromedriver

qa/Dockerfile

 FROM ruby:2.3
 LABEL maintainer "Grzegorz Bizon <grzegorz@gitlab.com>"
 
+ENV CHROME_VERSION 59.0.3071.104-1
+ENV DRIVER_VERSION 2.30
+
 ##
 # Update APT sources and install some dependencies
 #
@@ -8,15 +11,16 @@ RUN sed -i "s/httpredir.debian.org/ftp.us.debian.org/" /etc/apt/sources.list
 RUN apt-get update && apt-get install -y wget git unzip xvfb
 
 ##
-# Google Chrome 59 is the first version with headless support
+# Install Google Chrome version with headless support
 #
-RUN wget -q https://dl.google.com/linux/chrome/deb/pool/main/g/google-chrome-stable/google-chrome-stable_59.0.3071.86-1_amd64.deb
-RUN dpkg -i google-chrome-stable_59.0.3071.86-1_amd64.deb; apt-get -fy install
+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
 
 ##
 # Install chromedriver to make it work with Selenium
 #
-RUN wget -q https://chromedriver.storage.googleapis.com/2.29/chromedriver_linux64.zip
+RUN wget -q https://chromedriver.storage.googleapis.com/$DRIVER_VERSION/chromedriver_linux64.zip
 RUN unzip chromedriver_linux64.zip -d /usr/local/bin
 
 RUN apt-get clean