text: Title: ISODate parse can use std library
  Body: Currently `ISODate`'s `parse` uses `dateutil`:
  https://github.com/betodealmeida/shillelagh/blob/7afaf13ec822f8c56895a8aec6ad77a7de2ea600/src/shillelagh/fields.py#L323-L328
  
   however as of Python 3.7, [`date.fromisoformat`](https://docs.python.org/3/library/datetime.html#datetime.date.fromisoformat) should work and be faster + less permissive (it doesn't try to guess the format)