Install docker using docker repo instead of convenience script

This approach will be more stable than depending on a convenience
script provided by docker

ref: https://docs.docker.com/install/linux/docker-ce/ubuntu/#install-using-the-convenience-script

Author: soapy1

plugins/provisioners/docker/cap/redhat/docker_install.rb

@@ -8,11 +8,14 @@ def self.docker_install(machine)
               machine.ui.warn("Docker is not supported on RHEL 8 machines.")
               raise DockerError, :install_failed
             end
-            
+
             machine.communicate.tap do |comm|
               comm.sudo("yum -q -y update")
               comm.sudo("yum -q -y remove docker-io* || true")
-              comm.sudo("curl -fsSL https://get.docker.com/ | sh")
+              comm.sudo("yum install -y -q yum-utils")
+              comm.sudo("yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo")
+              comm.sudo("yum makecache")
+              comm.sudo("yum install -y -q docker-ce")
             end
 
             case machine.guest.capability("flavor")