Add notice inconceivable (#1430)

Author: RalfJung

crates/inconceivable/RUSTSEC-0000-0000.md

@@ -0,0 +1,20 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "inconceivable"
+date = "2022-09-28"
+informational = "notice"
+url = "https://crates.io/crates/inconceivable"
+
+[versions]
+patched = []
+```
+
+# Library exclusively intended to inject UB into safe Rust.
+
+Quoting from the crate description:
+
+> This crate is created purely to inject undefined behavior into stable, safe rust.
+
+Specifically, the `inconceivable!` macro is insta-UB if the `ub_inconceivable` feature is enabled by *any* reverse dependency.
+The value this adds is questionable, and hides `unsafe` code from naive analysis.