changed docker checking line to check for docker command

debian/debian-essentials.sh

@@ -211,7 +211,7 @@ if [[ -d /etc/docker ]]
 fi
 
 # update lazydocker
-if [[ -f /etc/docker/daemon.json ]]
+if command -v docker &> /dev/null
     then
         curl -s https://raw.githubusercontent.com/jesseduffield/lazydocker/master/scripts/install_update_linux.sh | bash
         mv /root/.local/bin/lazydocker /usr/local/bin