fix: checkEnoughStock함수 guard 조건부 수정 #1

- 재고랑과 필요수량이 같은 경우를 누락하여 등호 추가

JuiceMaker/JuiceMaker/Model/FruitStore.swift

@@ -63,7 +63,7 @@ class FruitStore {
     }
 
     func checkEnoughStock(from index: Int, for count: Int) throws {
-        guard inventory[index].count > count else {
+        guard inventory[index].count >= count else {
             throw FruitStoreError.lackOfStock(stockNeeded: count - inventory[index].count)
         }
     }