Fix. set heigh/format to row
Fix. set heigh/format to row

```Lua
sh:set_row(0, nil, bk:add_format{align = "center"})

bk:close() --< worksheet.lua:2405: attempt to index local 'row_xf' (a number value)
```

moteus/xlsxwriter.lua,moteus/xlsxwriter.lua,moteus/xlsxwriter.lua,moteus/xlsxwriter.lua