fix: cell.style.fill problems

[styunan]

Summary

After all the borders of (A1: B1) are set, read the excel file, and then change the background color of cell A1. The background color of cell B1 will also change.
create test_a.xlsx

  const wb = new ExcelJS.Workbook();
  const worksheet = wb.addWorksheet('Sheet1');
  const border = {"left":{"style":"thin"},"right":{"style":"thin"},"top":{"style":"thin"},"bottom":{"style":"thin"}};
  worksheet.getCell('A1').style.border = border;
  worksheet.getCell('A1').value = 'A1';
  worksheet.getCell('B1').style.border = border;
  worksheet.getCell('B1').value = 'B1';
  wb.xlsx.writeFile(path.resolve('./spec/unit/doc/test_a.xlsx'));

Then read excel

  const wb = new ExcelJS.Workbook();
  const workbook = await wb.xlsx.readFile('./spec/unit/doc/test_a.xlsx');
  workbook.getWorksheet(1).getCell('A1').style.fill = {
    type: 'pattern',
    pattern: 'solid',
    fgColor: { argb: 'FFFF0000' },
    bgColor: { indexed: 64 }
  };
  console.log(workbook.getWorksheet(1).getCell('A1').style.fill === workbook.getWorksheet(1).getCell('B1').style.fill);
  // **true**

  console.log(workbook.getWorksheet(1).getCell('B1').style.fill);
  console.log(workbook.getWorksheet(1).getCell('A1').style.fill);
  workbook.xlsx.writeFile(path.resolve('./spec/unit/doc/test_a0000.xlsx'));

fill A1 with red solid but A2 also red solid

Test plan spec\unit\utils

A simple test is included in spec/unit/utils/utils.spec.js