animals variants

🐛 Bug Fixes

• Fixed an issue where cows would change their type when moving between biomes.
  • Example: A cold cow (from the Taiga) would become temperate after moving to a Plains biome and reloading the game.
  • The cow's variant is now permanently saved in the entity, thanks to cputnam-a11y.

✨ New Features

• Added Warm Cows 🐄🔥
  • These cows now spawn in warm biomes.
  • For a full list of spawn locations, see the Minecraft Wiki.
  • 1.21 support