added fruit drop limit variables

scripts/drop_manager.gd

@@ -3,6 +3,8 @@ extends Node2D
 @onready var player = get_node("/root/Game/Player")
 @onready var bar = get_node("/root/Game/CanvasLayer/ProgressBar")
 signal leveled_up
+@export var fruit_drop_threshold: int = 7
+@export var fruit_drop_ceiling: int = 15
 
 # Called when the node enters the scene tree for the first time.
 func _ready() -> void: