remove api that was scheduled for removal

patches/api/0246-living-entity-allow-attribute-registration.patch

@@ -0,0 +1,25 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: ysl3000 <yannicklamprecht@live.de>
+Date: Sat, 24 Oct 2020 16:37:21 +0200
+Subject: [PATCH] living entity allow attribute registration
+
+
+diff --git a/src/main/java/org/bukkit/attribute/Attributable.java b/src/main/java/org/bukkit/attribute/Attributable.java
+index 0ed96b5af0e6e93590882e0ad8239221bcc3f688..474ed1df364a5ca18661d0fbc29901760e39cb07 100644
+--- a/src/main/java/org/bukkit/attribute/Attributable.java
++++ b/src/main/java/org/bukkit/attribute/Attributable.java
+@@ -17,4 +17,14 @@ public interface Attributable {
+      */
+     @Nullable
+     AttributeInstance getAttribute(@NotNull Attribute attribute);
++
++    // Paper start
++    /**
++     * Registers a generic attribute to that attributable instance.
++     * Allows it to add attributes not registered by default to that entity.
++     *
++     * @param attribute the generic attribute to register
++     */
++    void registerAttribute(@NotNull Attribute attribute);
++    // Paper end
+ }