`RSSFeed` model ImportError when locale not set

[Jonny Saunders]

locale.getdefaultlocale() (which is deprecated) and locale.getlocale() can return None if language cannot be determined: https://docs.python.org/3/library/locale.html#locale.getdefaultlocale

Since the default in the model calls the function directly (rather than using default_factory), the model can't be imported at all:

fastapi_rss/fastapi_rss/models/feed.py

Line 23 in 558151c

 language: str = get_locale_code() 

due to a predictable AttributeError: NoneType object has no attribute lower thrown here:

fastapi_rss/fastapi_rss/utils.py

Line 14 in 558151c

 return locale.getdefaultlocale()[0].lower() 

to fix:

• use default_factory so the model can be imported and patched if needed
• make language optional, and check for None type in get_locale_code

[Simon Bordeyne]

This has been deployed on PyPI