Change node source repository

[alexpado]

While building the docker image the following warning was displayed:

================================================================================
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
================================================================================

                           SCRIPT DEPRECATION WARNING


  This script, located at https://deb.nodesource.com/setup_X, used to
  install Node.js is deprecated now and will eventually be made inactive.

  Please visit the NodeSource distributions Github and follow the
  instructions to migrate your repo.
  https://github.com/nodesource/distributions

  The NodeSource Node.js Linux distributions GitHub repository contains
  information about which versions of Node.js and which Linux distributions
  are supported and how to install it.
  https://github.com/nodesource/distributions


                          SCRIPT DEPRECATION WARNING

================================================================================
▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
================================================================================

TO AVOID THIS WAIT MIGRATE THE SCRIPT
Continuing in 60 seconds (press Ctrl-C to abort) ...

So following instructions on the repository linked in that message (https://github.com/nodesource/distributions), I modified the Dockerfile to use the new installation method.

I tested it and both node and npm install just fine.