Elytra Nerf

• Reverted durability change made in 1.2.0, once again matching 1.18 experimental snapshot 7.
• Elytra will no longer activate while jumping in a 2 block high tunnel.

• Added support for 1.21.4.
• Speed boosts from firework rockets have been slightly nerfed.
• Durability consumed when a firework rocket is used has been slightly increased.

• Added support for 1.21.3.

Initial release.