Attempt to recreate the behavior described in https://github.com/natergj/excel4node/issues/161

DataValidationIssue161

const xl = require('excel4node');

const wb = new xl.Workbook();
const ws = wb.addWorksheet('sheet1');
const ws2 = wb.addWorksheet('sheet2');

ws2.cell(1,1).string('value 1');
ws2.cell(2,1).string('value 2');
ws2.cell(3,1).string('value 3');

ws.addDataValidation({ type: 'list', sqref: 'A2:'+'A20', formulas: [ '=sheet2!$A$1:$A$3' ] });

wb.write('DataValidationTest.xlsx');