support expanduser() for dotenv_path

It would be great if one can place API_KEYs in one .env file outside github repositories, 
currently dotenv_path argument does not support "~" as home_path.

Please consider improving this line at https://github.com/theskumar/python-dotenv/blob/main/src/dotenv/main.py#L45
as 
```
self.dotenv_path: Optional[StrPath] = Path(dotenv_path).expanduser()
```

Thanks
