SPIGOT-4784: Collar colour API for Cats

By: md_5 <git@md-5.net>

paper-api/src/main/java/org/bukkit/entity/Cat.java

@@ -1,5 +1,6 @@
 package org.bukkit.entity;
 
+import org.bukkit.DyeColor;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -22,6 +23,21 @@ public interface Cat extends Animals, Tameable, Sittable {
      */
     public void setCatType(@NotNull Type type);
 
+    /**
+     * Get the collar color of this cat
+     *
+     * @return the color of the collar
+     */
+    @NotNull
+    public DyeColor getCollarColor();
+
+    /**
+     * Set the collar color of this cat
+     *
+     * @param color the color to apply
+     */
+    public void setCollarColor(@NotNull DyeColor color);
+
     /**
      * Represents the various different cat types there are.
      */