fix: locales like 'pt_BR' 'fr_BE' will work when send to the frontend

[crazynds]

I recently had a problem using laravel-file-maneger. When I opened the manager it didnt show any file, only folder. Trying to find the problem I found the following error in the frontend:

So looking more deep I found the problem is the same as here: formatjs/formatjs#2440

Basically, if you use intl for internationalization, it wont work if it couldnt find a valid lang for the case, so, 'pt_BR' is a invalid lang, but 'pt-BR' is valid.

But why dont I change that in the app.php config?

Because php use the oposite 😃.
You can see here: https://www.php.net/manual/en/intlcalendar.getavailablelocales.php

So, this PR only replace all _ in a locale with -. I checked and any Intl locales use '_' in their names.

[crazynds]

@alexusmai Could you give some attention to this?
I think it should take less than 2 minutes.