code: function createBanner() {
    var today = gutil.date(new Date(), 'yyyy-mm-dd'); // today, formatted as yyyy-mm-dd
    var version = require('./package.json').version;
  
    return String(fs.readFileSync(HEADER))
        .replace('@@date', today)
        .replace('@@version', version);
  }
docs: generate banner with today's date and correct version