Add Keys.MAX_GROWTH_STAGE (#2511)

Author: MrHell228

src/main/java/org/spongepowered/api/data/Keys.java

@@ -2298,6 +2298,13 @@ public final class Keys {
      */
     public static final Key<Value<Ticks>> MAX_FROZEN_TIME = Keys.key(ResourceKey.sponge("max_frozen_time"), Ticks.class);
 
+    /**
+     * The max growth stage of a {@link BlockState}.
+     * e.g. {@link BlockTypes#CACTUS} or {@link BlockTypes#WHEAT} etc.
+     * Readonly
+     */
+    public static final Key<Value<Integer>> MAX_GROWTH_STAGE = Keys.key(ResourceKey.sponge("max_growth_stage"), Integer.class);
+
     /**
      * The maximum health of a {@link Living}.
      *