It is not Github that is at fault. It is #Rust projects that have a dependency on yaml-rust and - via Github Actions - see CI reporting a message from RUSTSEC. Here's that advisory:
https://rustsec.org/advisories/RUSTSEC-2024-0320.html
The advisory in turn contains a reference to a yaml-rust issue about the unmaintained status, which is why you see all the cross-links in it: