通过 customRender: (text,record,index) => `${index+1}`, 自动生成序号列，不用再写template

columns: [
       {
            title: '序号',
            dataIndex: 'index',
            key: 'index',
            width: 50,                    
            fixed: 'left',
            customRender: (text,record,index) => `${index+1}`, // 关键句
       },
       ....
]