vagrant: fix docker install script

The key fingerprint doesn't seem to have changed, but something about
the old key installation command failed for me and broke vagrant up.

scripts/vagrant-linux-priv-docker.sh

@@ -1,9 +1,9 @@
 #!/usr/bin/env bash
 
+# Source: https://docs.docker.com/engine/install/ubuntu/
+
 # Add the Docker repository
-apt-key adv \
-	      --keyserver hkp://p80.pool.sks-keyservers.net:80 \
-	      --recv-keys 9DC858229FC7DD38854AE2D88D81803C0EBFCD88
+curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
 add-apt-repository \
 	  "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
 	$(lsb_release -cs) \
@@ -12,7 +12,7 @@ add-apt-repository \
 # Update with i386, Go and Docker
 apt-get update
 
-apt-get install -y docker-ce
+apt-get install -y docker-ce docker-ce-cli containerd.io
 
 # Restart Docker in case it got upgraded
 systemctl restart docker.service