Add dupemod to README (#44)

Author: ScribbleTAS

README.md

@@ -13,6 +13,11 @@ Needs Fabric API
 - Savestates
   - Saving (<kbd>J</kbd>)
   - Loading (<kbd>K</kbd>)
+- Item Duplication
+  1. Press Pause to save the game with the item in your inventory
+  2. Throw out the item out of your inventory or put it in a chest
+  3. Press <kbd>O</kbd>
+  4. Rejoin the world
 
 ## Translations
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