Upgrade Node.js to fulfill autoprefixer's min version requirement

Author: tniezg

Dockerfile

@@ -1,6 +1,8 @@
 # This dockerfile is used to build sandbox image for docker clouds. It's not meant to be used in projects
 FROM ruby:2.5.1
-RUN apt-get update -qq && apt-get install -y build-essential libpq-dev nodejs
+RUN apt-get update -qq && \
+  apt-get install -y build-essential libpq-dev && \
+  curl -sL https://deb.nodesource.com/setup_8.x | bash - && apt-get install -y nodejs
 RUN mkdir /spree
 WORKDIR /spree
 ADD . /spree