docker repository has been deprecated

[jeh0s]

https://apt.dockerproject.org/repo has been deprecated

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/