Add futuresMultipleOrders function by Wostafa

Author: jaggedsoft

README.md

@@ -80,6 +80,26 @@ console.info( await binance.futuresMarketBuy( 'BNBUSDT', 5 ) );
 ```js
 console.info( await binance.futuresMarketSell( 'TRXUSDT', 1 ) );
 ```
+
+#### Futures Place Multiple Orders
+```js
+let orders = [
+  {
+  symbol:"BTCUSDT",
+  side: "BUY",
+  type: "MARKET",
+  quantity: "0.01",
+  },
+  {
+  symbol:"BNBUSDT",
+  side: "SELL",
+  type: "MARKET",
+  quantity: "0.5",
+  }
+]
+console.info( await binance.futuresMultipleOrders(orders) );
+```
+
 #### Futures Market Orders: Get the fill price using newOrderRespType
 ```js
 console.info( await binance.futuresMarketBuy( 'BNBUSDT', amount, { newOrderRespType: 'RESULT' } ) );

node-binance-api.js

@@ -4111,6 +4111,11 @@ let api = function Binance( options = {} ) {
         futuresMarketSell: async ( symbol, quantity, params = {} ) => {
             return futuresOrder( 'SELL', symbol, quantity, false, params );
         },
+        
+        futuresMultipleOrders: async ( orders = [{}] ) => {
+            let params = { batchOrders: JSON.stringify(orders) };
+            return promiseRequest( 'v1/batchOrders', params, { base:fapi, type:'TRADE', method:'POST'} );
+        },
 
         futuresOrder, // side symbol quantity [price] [params]