Locale Import made relative

**Describe the bug**

Locale cannot be imported when name of package is changed.

**Expected behavior**

That imports would be relative "in package" so it can continue to work.

**Information**
- Day.js Version ALL
- OS: ALL
- Browser ALL
- Time zone: ALL

**Fix**
inside locale/*.*
```diff
- import dayjs from 'dayjs'
+ import dayjs from '..'
```

Start with the files under locale/*.* and review how they import dayjs when the package name changes. Update the locale imports to use the package-relative path shown in the issue, then verify that locales can still be imported after the package name is changed.

Written by the indexing model from the issue text.