fix no result is printed on local csv file examples on demo page

Author: berkinanik

docs/src/components/screens/Demo.js

@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useEffect, useState } from 'react';
 import { Tab, Tabs, TabList, TabPanel } from 'react-tabs';
 
 import { usePapaParse, useCSVReader, lightenDarkenColor, formatFileSize } from 'react-papaparse';
@@ -169,6 +169,14 @@ export default function Demo() {
   }
 ]`);
 
+  useEffect(() => {
+    if (csvData) {
+      console.log('---------------------------');
+      console.log(csvData);
+      console.log('---------------------------');
+    }
+  }, [csvData]);
+
   const handleSelect = (index) => {
     setTabIndex(index);
   };