Prepare for merging from rust-lang/rust

This updates the rust-version file to cc328c12382f05d8ddf6ffc8139deb7985270ad8.
diff --git a/src/doc/rustc-dev-guide/rust-version b/src/doc/rustc-dev-guide/rust-version
index 25bb5e9..8c841aa 100644
--- a/src/doc/rustc-dev-guide/rust-version
+++ b/src/doc/rustc-dev-guide/rust-version
@@ -1 +1 @@
-69d4d5fc0e4db60272aac85ef27ecccef5764f3a
+cc328c12382f05d8ddf6ffc8139deb7985270ad8