"make demo" can't find the theme for exampleSite

[wh0pper]

Describe the bug
Love what you've built here. While working on setting up a neofeed of my own, I encountered an error when trying to run the exampleSite with "make demo" where hugo CLI can't find the theme. I have a fix for this that makes the exampleSite an independent go module, then links the theme as a dependency via the local parent directory to allow the theme to be developed on locally via the exampleSite to demonstrate changes

To Reproduce
Steps to reproduce the behavior:

1. fork original repo
2. clone the fork to local
3. from the project root, run the "make demo" command
4. See Error: module "neofeed" not found. Hugo fails to serve the site

Expected behavior
I expect the exampleSite to run locally with the neofeed theme demonstrated

Screenshots

Desktop (please complete the following information):

• OS: macOS Ventura 13.0.1
• Browser: Chrome
• Version: 107.0.5304.110