[Bug] Fix url of DjangoCon US 2024

[dragid10]

Currently when trying to click on the DjangoCon conference link, it doesn't have the correct url. This is because we're not including the https to the url, so jekyll assumes that its an internal link.

The solution is just adding the https:// to the url.

I'd like to work on this issue

[dragid10]

Also I apologize for working backwards on this. I saw the issue and did a quick in-browser fix