Add an unmaintained crate advisory for yaml-rust

Closes: rustsec#1921

crates/yaml-rust/RUSTSEC-2024-0320.md

@@ -0,0 +1,26 @@
+```toml
+[advisory]
+id = "RUSTSEC-2024-0320"
+package = "yaml-rust"
+date = "2024-03-20"
+informational = "unmaintained"
+url = "https://github.com/rustsec/advisory-db/issues/1921"
+
+[versions]
+patched = []
+unaffected = []
+```
+
+# yaml-rust is unmaintained.
+
+The maintainer seems [unreachable](https://github.com/chyh1990/yaml-rust/issues/197).
+
+Many issues and pull requests have been submitted over the years
+without any [response](https://github.com/chyh1990/yaml-rust/issues/160).
+
+## Alternatives
+
+Consider switching to the actively maintained `yaml-rust2` fork of the original project:
+
+- [yaml-rust2](https://github.com/Ethiraric/yaml-rust2)
+- [yaml-rust2 @ crates.io](https://crates.io/crates/yaml-rust2))