Added luckperms integration for the MaxShops function, allowing different groups to have different values, set in the config
Added an UpdateChecker class, reminding admins to update the plugin when viable.
Made the shop values non-global, so multiple people buying shouldn't affect each other.
And added a /diamondshop help command to describe to players what to put on a sign
No character limit on signs, if you fill it out all the way it will search for an item that contains those characters. EX = Firework_Rock now searches for items with that in the name.
Tested all the way back to 1.13
Chests out of items will now only say "Out of stock" instead of also saying "Out of items"