1.12.16 - Configuration Phase fixes and allow duplicate pack url/hash/uuid
Fixes issues with sending packs in the Configuration Phase on Velocity
Allow pack (variant)s to have duplicate urls, hashes and uuids. Now only a warning is printed. (There might be issues with detecting which pack was sent in some special cases e.g. when the backend Minecraft server sends a pack in certain cases though so be aware of that. Ideally you should not be running such a setup hence why it is a warning!)