Fixes

• Make PacketEvents optional as intended
• Fix GeyserExtras-Extension update checker to redirect to modrinth instead of GitHub as they support Geyser Extensions now :D
• Revert spigot API back to 1.16 as it would crash on anything lower than 1.21.9/10

Code Changelog: https://github.com/GeyserExtras/GeyserExtras/compare/2.0.0-BETA-9...2.0.0-BETA-10