Fixed mod detection by modern NeoForge

Fixed Forge crash caused by incorrect metadata (#6)

• Added support for Minecraft 1.21 (should support 1.13.2 as well if your loader API supports it, not tested)
• Added protected_from_despawn tag so you can easily exclude protected items by it from auto-clearing in your mod/plugin/datapack
• Tweaked the feedback message
• Fixed links, license and other data (again)

• Added support for Minecraft 1.13.2 and 1.21+
• Added protected_from_despawn tag so you can easily exclude protected items by it from auto-clearing in your mod/plugin/datapack
• Tweaked the feedback message

Initial release

• Despawn protection mechanic
• Optional feedback with number of saved items (disabled by default)