Add unmaintained advisory for iron

Author: jayvdb

crates/iron/RUSTSEC-0000-0000.md

@@ -0,0 +1,19 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "iron"
+date = "2025-09-08"
+url = "https://github.com/rustsec/advisory-db/issues/1424"
+informational = "unmaintained"
+
+[versions]
+patched = []
+```
+
+# iron crate is unmaintained
+
+The `iron` crate is no longer actively maintained.  If you rely on this crate, consider switching to a maintained alternative.
+
+## Recommended alternatives
+
+See [this comparison](https://github.com/flosse/rust-web-framework-comparison#server-frameworks) for popular alternatives.