[1.x] Update rustc-rayon to 0.5, and release 1.9.3

(cherry picked from commit 861fad7)

Author: cuviper

Cargo.toml

@@ -22,7 +22,7 @@ rayon = { version = "1.5.3", optional = true }
 
 # Internal feature, only used when building as part of rustc,
 # not part of the stable interface of this crate.
-rustc-rayon = { version = "0.4", optional = true }
+rustc-rayon = { package = "rustc-rayon", version = "0.5", optional = true }
 
 [dependencies.hashbrown]
 version = "0.13"

RELEASES.md

@@ -31,6 +31,10 @@
   - The `serde_seq` module has been moved from the crate root to below the
     `map` module.
 
+- 1.9.3
+
+  - Bump the `rustc-rayon` dependency, for compiler use only.
+
 - 1.9.2
 
   - `IndexMap` and `IndexSet` both implement `arbitrary::Arbitrary<'_>` and