Add changelog.

changelog.md

@@ -1,2 +1,18 @@
-## Changes
-- Updated to 1.21.4 Minecraft.
+Minor update to add the groundwork for a shield-related features.
+
+
+## Additions
+- Added new class for easily executing callbacks from an item.
+- Added new interface, BlockingItem.
+  - Items with the ability to block attacks should implement this interface.
+  - It contains methods that allow the item to configure the nature of its blocking.
+    - Cooldown duration when disabled.
+    - How many ticks the item must be used for until it is actively blocking attacks.
+    - Callbacks
+      - Damaging the shield.
+      - Post-block actions.
+- Added enchantment callback for post-block actions.
+- Added enchantment context (for conditions) for post-block actions.
+  - In this context, the target is the owner of the enchanted item, the one who blocked the attack.
+- Added debug shield item and debug blocking enchantment for developers.
+- **[LilyLib]** Enchantment descriptions now also generate a `.description` key as well as the existing `.desc` key.