support expanduser() for dotenv_path

[wgong]

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

[stuaxo]

@wgong this would have a better chance of being merged as a PR

[wgong]

thanks for considering this enhancement

[theskumar]

@wgong I believe this is a safe change, can be supported. cc: @bbc2