Custom format creating wrong date

Parsing the date `31/01/2019` (pt-br style) using `dayjs_plugin_customParseFormat` is creating a wrong date.

```js
dayjs.extend(dayjs_plugin_customParseFormat);

dayjs('31/01/2019', 'DD/MM/YYYY')
// => 2019-03-03T00:00:00-03:00
```

<https://jsfiddle.net/dpb4hfnk/>