Merge pull request #582 from SeleniumHQ/update-firefox-56

Upgrade FF version 56.0

Author: diemol

.github/ISSUE_TEMPLATE.md

@@ -3,6 +3,8 @@ Image(s):
 <!-- node-chrome? hub? standalone-firefox? -->
 Docker-Selenium Image Version(s):  
 <!-- 3, 3.4, 3.5.3-boron etc -->
+Docker Version:  
+<!-- 17.09.0-ce, 17.06.2-ce etc -->
 OS: 
 <!-- Windows 10, OSX Yosemite, Centos6, etc -->
 

NodeFirefox/Dockerfile.txt

@@ -3,7 +3,7 @@ USER root
 #=========
 # Firefox
 #=========
-ARG FIREFOX_VERSION=55.0.3
+ARG FIREFOX_VERSION=56.0
 RUN apt-get update -qqy \
   && apt-get -qqy --no-install-recommends install firefox \
   && rm -rf /var/lib/apt/lists/* /var/cache/apt/* \