Update Docker APT references in Vagrant

[adamczi]

Hi, I noticed Vagrant version of JuiceShop does not provision, due to errors with apt repository:

default: W: The repository 'https://apt.dockerproject.org/repo ubuntu-xenial Release' does not have a Release file.
default: E: Failed to fetch https://apt.dockerproject.org/repo/dists/ubuntu-xenial/main/binary-amd64/Packages  404  Not Found
default: E: Some index files failed to download. They have been ignored, or old ones used instead.

and therefore:

default: E: Package 'docker-engine' has no installation candidate

Entering https://apt.dockerproject.org/repo/ shows a notice that dockerproject.org shuts down in the end of March 2020:

Notice: Shutting down dockerproject.org APT and YUM repos 2020-03-31

Docker will be shutting down the deprecated APT and YUM repositories hosted at "dockerproject.org" and "dockerproject.com" on the 31st of March 2020.

We noticed that this project is referencing one of these repositories, and recommend updating to use the "download.docker.com" repository to prevent disruption.

More info: https://www.docker.com/blog/changes-dockerproject-org-apt-yum-repositories/ 

So I:

• changed public key reference to official Ubuntu keyserver
• changed apt repository line to docker.com
• replaced deprecated docker-engine installation to docker-ce
• added set -e script option to stop on errors (so with previous errors it would stop on dockerproject.org repo error and not go further trying to download docker-engine)

[bkimminich]

Cool, thanks a lot! As Vagrant seems to be so rarely used, I'm even more glad you found and fixed this proactively!

[bkimminich]

Please send me an email or Gitter-PM with your home address and I'll send you a nice collection of stickers!