Dungeons and Taverns Ancient City Overhaul

Fixed bug caused by missing tag :)

• Added Spears to the loot tables. that's it.

• Added an advancement for discovering an Ancient City
• Added a hidden advancement for trading Swift Sneak from a secret librarian of the Ancient City. To access this, the main DnT datapack is required.

• Updated Packformats format to 1.21.9 formats format since it now includes minor datapack version inside the format.

Updated to 1.21.5