I removed the auto-downloading feature of the MC server jar since the naming has changed form MC 1.12 to 1.13. Instead you now must run vanillacord on an existing local server jar.
Usage:
java -jar vanillacord.jar <filename>
For example, to setup a bungee-enabled minecraft server for version 1.13, do this:
wget https://launcher.mojang.com/mc/game/1.13/server/d0caafb8438ebd206f99930cfaecfa6c9a13dca0/server.jar
java -jar vanillacord.jar server.jar
After that you can start the patched Minecraft server like this:
java -jar server-bungee.jar