Locale "pt-BR" The first letter is not capitalized.

**Describe the bug**
hello,

I am using 'dayjs/locale/pt-br' to return the months and years in the datePicker, but the first letter does not stay capitalized. It appears like this: "junho 2023" instead of "Junho 2023", as shown in the image below.


**Expected behavior**
return: "Julho 2023"

**Information**
- Day.js Version [e.g. v1.0.0]
- OS: [e.g. iOS]
- Browser [e.g. chrome 62]
- Time zone: [e.g. GMT-07:00 DST (Pacific Daylight Time)]

Start by inspecting the dayjs/locale/pt-br locale implementation and the date-formatting path used for month names. Reproduce the reported output for "junho 2023" and verify the change against the expected "Julho 2023" wording; the issue does not name a test file or provide version and environment details.

Written by the indexing model from the issue text.