Add unmaintained advisory for rustc-serialize

Author: llooFlashooll

crates/rustc-serialize/RUSTSEC-0000-0000.md

@@ -0,0 +1,16 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "rustc-serialize"
+date = "2025-04-28"
+url = "https://github.com/rust-lang-deprecated/rustc-serialize/issues"
+informational = "unmaintained"
+
+[versions]
+patched = []
+```
+
+# rustc-serialize is unmaintained
+
+`rustc-serialize` will no longer be maintained as declared by the developer. By fuzzing the package, we can identify multiple vulnerabilities.
+The project has been archived and cannot submit issues. The developer has recommended using the `serde` crate instead.