feat:修改下单问题

@@ -110,8 +110,8 @@ class Order
         $order = [
             'category' => 'linear',
             'symbol' => $symbol,
-            'qty' => round($this->qty, $symbolInfo->qtyPrec),
-            'price' => round($this->price, $symbolInfo->pricePrec),
+            'qty' => (string)round($this->qty, $symbolInfo->qtyPrec),
+            'price' => (string)round($this->price, $symbolInfo->pricePrec),
             'orderLinkId' => $this->cliOrdId,
         ];
         if ($this->ordType == "MARKET") {