fix delete rates

lib/data/provider/rate_data_provider.dart

@@ -160,7 +160,7 @@ class RateDataProvider {
   }
 
   Future<void> deleteCustomDuty(String id) async {
-    return await requestAPI("/custom_duties", "PUT",
+    return await requestAPI("/custom_duties", "DELETE",
         payload: {"id": id}, token: await getToken());
   }
 
@@ -175,7 +175,7 @@ class RateDataProvider {
   }
 
   Future<void> deleteDiscountByWeight(String id) async {
-    return await requestAPI("/discounts_by_weight", "PUT",
+    return await requestAPI("/discounts_by_weight", "DELETE",
         payload: {"id": id}, token: await getToken());
   }
 }