Upgrade Nginx to version 1.20.0 or 1.21.0 due to security issues

[Alcatraz077]

I believe this is the correct repo for the nginx instance used by lan-cache. I've ran a security scan via Nessus, and came across multiple security vulnerabilities. Updated the underlying server, as well as the containers. Re-ran the scan, and vulnerabilities still exist. As such, I'd like to report them to you and request you update the version of nginx used by lan-cache projects to version 1.20.0 or 1.21.0, as this will close all vulnerabilities listed herein.

The one of most concern is an RCE vulnerability with a CVE score of 9.4. Attached are screenshots from the scan. This scan did take place via the LAN of course, but I'd still rather report these to have it patched if possible.

Attached are screenshots.