Additions:
- Added 1.20.6 and 1.21 support.

General Changes:
- Bumped PyroLib to v1.4.2

Fixes:
- Fixed an issue with fall damage and some entities dying.
- Fixed an issue where some entities were available to be set as spawner types but instead should be blocked.
- Fixed an issue with placing spawners in survival mode and the entity type not being set.

Notes:
- The next few updates will consist of Spawner & Entity stacking, more settings and configuration options, and changes to how the upgrade system works to allow you to create a spawner with an infinite number of upgrades.