1.17.6 - Bugs fixed

Changes:

• Fixed bug that would create "ghost players" when someone joined while not whitelisted.
• Fixed bug in scenario voting where blacklisted scenarios could be selected when nobody voted.
• Added support for AttributeModifier slots.
• Added support for leather armor colors.
• Fixed issue that would cause all players to spawn in one corner of the deathmatch arena when the initial border size was under 100 blocks.