Filter on a Single Select field

Right now we can only filter the items we want to update on a project by looking at certain field types. Specifically:
- Text
- Number
- Date

I want to add the ability to filter an item by checking of its single select fields. For example if an item in my project has field "Team" which can be a single select of `Frontend`, `Backend` and `API`, I want to be able to filter based on the "Team" selection.

Start by locating the existing filtering logic for Text, Number, and Date fields, then trace how GitHub Projects field values are read. Add filtering for a single-select field such as Team, and verify that Frontend, Backend, and API selections can be matched as filter values.

Written by the indexing model from the issue text.