Support HTTPS

[clue]

GitHub started supporting HTTPS for custom domains a few days ago, so it would be awesome if ndjson.org would also be available via HTTPS.

Right now, accessing it via HTTPS results in a certificate mismatch error. Fixing this is simply a matter of updating the DNS A records as per this article: https://help.github.com/articles/setting-up-an-apex-domain/#configuring-a-records-with-your-dns-provider

[clue]

Friendly ping, is there anything we can do to help with this? 👍

This should be an easy pick, it looks like only the DNS records have to be updated as per https://help.github.com/en/github/working-with-github-pages/managing-a-custom-domain-for-your-github-pages-site#configuring-an-apex-domain