Fixed a bug where players would still be able to pay for a drink, but not receive it if their inventory was full. Shoutout to @lukenrip for reporting it.
You must regenerate your messages.yml file, or add the following lines manually.
Code (YAML):
# Sent to a player when they try to buy a drink with a full inventory fullInventory: "&cSorry, your inventory is too full to buy a drink!"