Update SpongeSchematic format to version 2.

Allows saving and loading entities and biomes.

worldedit-core/src/main/java/com/sk89q/worldedit/extension/platform/Platform.java

@@ -45,6 +45,13 @@ public interface Platform {
      */
     Registries getRegistries();
 
+    /**
+     * Gets the Minecraft data version being used by the platform.
+     *
+     * @return the data version
+     */
+    int getDataVersion();
+
     /**
      * Checks if a mob type is valid.
      *