add crossbeam advisories for incorrect (unsound) zeroed memory (#1231)

* add crossbeam queue advisory

* also add crossbeam-channel issue

Author: RalfJung

crates/crossbeam-channel/RUSTSEC-0000-0000.md

@@ -0,0 +1,18 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "crossbeam-channel"
+date = "2022-05-10"
+informational = "unsound"
+url = "https://github.com/crossbeam-rs/crossbeam/pull/458"
+
+[versions]
+patched = [">= 0.4.3"]
+```
+
+# Channel creates zero value of any type
+
+Affected versions of this crate called `mem::zeroed()` to create values of a user-supplied type `T`.
+This is unsound e.g. if `T` is a reference type (which must be non-null).
+ 
+The flaw was corrected by avoiding the use of `mem::zeroed()`, using `MaybeUninit` instead.

crates/crossbeam-queue/RUSTSEC-0000-0000.md

@@ -0,0 +1,18 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "crossbeam-queue"
+date = "2022-05-10"
+informational = "unsound"
+url = "https://github.com/crossbeam-rs/crossbeam/pull/458"
+
+[versions]
+patched = [">= 0.2.3"]
+```
+
+# `SegQueue` creates zero value of any type
+
+Affected versions of this crate called `mem::zeroed()` to create values of a user-supplied type `T`.
+This is unsound e.g. if `T` is a reference type (which must be non-null).
+ 
+The flaw was corrected by avoiding the use of `mem::zeroed()`, using `MaybeUninit` instead.

crates/crossbeam/RUSTSEC-0000-0000.md

@@ -0,0 +1,18 @@
+```toml
+[advisory]
+id = "RUSTSEC-0000-0000"
+package = "crossbeam"
+date = "2022-05-10"
+informational = "unsound"
+url = "https://github.com/crossbeam-rs/crossbeam/pull/458"
+
+[versions]
+patched = [">= 0.7.0"]
+```
+
+# `SegQueue` creates zero value of any type
+
+Affected versions of this crate called `mem::zeroed()` to create values of a user-supplied type `T`.
+This is unsound e.g. if `T` is a reference type (which must be non-null).
+ 
+The flaw was corrected by avoiding the use of `mem::zeroed()`, using `MaybeUninit` instead.