refactor: 리마인더 알림 타입 추가 (#8)

Author: unifolio0

src/main/java/com/wellmeet/notification/consumer/dto/NotificationType.java

@@ -9,4 +9,5 @@ public enum NotificationType {
     RESERVATION_CONFIRMED,
     RESERVATION_UPDATED,
     RESERVATION_CANCELED,
+    RESERVATION_REMINDER,
 }