Add support for Zotero's Date property

[samirunni]

• Followed same approach as Add abstract field #35
• Tested locally and confirmed to be working
• Went with a text type for the date instead of a date type because Zotero itself doesn't store that property as a date
  • For example, my test entries (journal articles) included dates of 2022-05
  • It makes the most sense for users to use a formula column on the Notion side to parse the date strings

[dvanoni]

@samirunni thanks so much for your contribution! 🙇

I completely agree with your decision to use a text property instead of a date property. I even have some items that only have the year in the date field, so text works perfectly.

I requested one minor change, but I tested locally and it seems to work great!

[dvanoni]

I went ahead and applied that small change. Thanks again for the contribution!

[samirunni]

@dvanoni - sorry, didn't see your prior comment until now. Thanks for merging!