Add advisory for data race in generator (#855)

crates/generator/RUSTSEC-0000-0000.md

@@ -0,0 +1,25 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "generator"
+date = "2020-11-16"
+url = "https://github.com/Xudong-Huang/generator-rs/issues/27"
+categories = ["memory-corruption"]
+keywords = ["concurrency"]
+
+[versions]
+patched = [">= 0.7.0"]
+```
+
+# Generators can cause data races if non-Send types are used in their generator functions
+
+The `Generator` type is an iterable which uses a generator function that yields
+values. In affected versions of the crate, the provided function yielding values
+had no `Send` bounds despite the `Generator` itself implementing `Send`.
+
+The generator function lacking a `Send` bound means that types that are
+dangerous to send across threads such as `Rc` could be sent as part of a
+generator, potentially leading to data races.
+
+This flaw was fixed in commit [`f7d120a3b`](https://github.com/Xudong-Huang/generator-rs/commit/f7d120a3b724d06a7b623d0a4306acf8f78cb4f0)
+by enforcing that the generator function be bound by `Send`.