+ Add 1.21.5 support
* Fix desynchronisation on anvil, beacon, cartography table, enchanting table, grindstone, merchant, smithing table, and stonecutter guis
* Fix viewers being incorrect for anvil, beacon, cartography table, enchanting table, grindstone, merchant, smithing table, and stonecutter guis
* Fix player closing gui clearing the gui for other viewers
- Remove 1.14 and 1.15 support