German dot not appearing in ordinal months

**Describe the bug**
When trying to display a german month like `Feb.`, using format `Do MMM`, dot does not appear.

**Expected behavior**
When using Do, `Feb.` should be displayed instead of `Feb`.

**Information**

Day.js Version: 1.10.4
OS: Mac

I am using

```
import localizedFormat from 'dayjs/plugin/localizedFormat'
dayjs(date).format(dateFormat)
```

Not sure if dayjs supports ordinals for months. If yes, which one is the syntax?

Start at the localizedFormat plugin and the format(dateFormat) entry point, then trace how German month names are selected for `Do MMM`. Compare the current output with the expected `Feb.` result and add coverage for this formatting case; done means German ordinal-month formatting includes the period without changing other locale output.

Written by the indexing model from the issue text.