fix method

Author: abuzuhri

Source/FikaAmazonAPI/Services/FulFillmentInboundService.cs

@@ -89,7 +89,7 @@ public async Task<ConfirmPreorderResult> ConfirmPreorderAsync(string shipmentId,
             queryParameters.Add(new KeyValuePair<string, string>("MarketplaceId", AmazonCredential.MarketPlace.ID));
             queryParameters.Add(new KeyValuePair<string, string>("NeedByDate", NeedByDate.ToString("YYYY-MM-DD")));
 
-            await CreateAuthorizedRequestAsync(FulFillmentInboundApiUrls.ConfirmPreorder(shipmentId), RestSharp.Method.Get, queryParameters);
+            await CreateAuthorizedRequestAsync(FulFillmentInboundApiUrls.ConfirmPreorder(shipmentId), RestSharp.Method.Put, queryParameters);
 
             var response = await ExecuteRequestAsync<ConfirmPreorderResponse>(RateLimitType.FulFillmentInbound_ConfirmPreorder);
             if (response != null && response.Payload != null)