New refgenconf requires python 3.8

[nsheff]

refgenconf/recipe.py:3: in <module>
    from functools import cached_property
E   ImportError: cannot import name 'cached_property' from 'functools' (/opt/hostedtoolcache/Python/3.7.14/x64/lib/python3.7/functools.py)

https://github.com/refgenie/refgenconf/blob/3f2ea03840b4e17b14dd57f0ae56109f40edf65f/refgenconf/recipe.py#L3

@stolarczyk Were you intending to make refgenconf depend on Python 3.8?

Or do you think of this as an optional thing that we should take out until 3.7 is deprecated?

[stolarczyk]

hmmm.. I don't remember what my intention was. But what you can do is:

1. drop py3.7 support
2. remove cached_property decorators to keep py3.7 support
3. use @property in conjunction with @functools.lru_cache to keep py3.7 support

Since memoization is a "nice to have" feature I'd likely go for option 2.