Upgrade rust/crates/protobuf to 2.22.1

Test: make
Change-Id: Ie58392a6f5fd045cb0adab0adbe869383d10c198
diff --git a/src/plugin.rs b/src/plugin.rs
index 007378f..77e1666 100644
--- a/src/plugin.rs
+++ b/src/plugin.rs
@@ -1,4 +1,4 @@
-// This file is generated by rust-protobuf 2.22.0-pre. Do not edit
+// This file is generated by rust-protobuf 2.22.0. Do not edit
 // @generated
 
 // https://github.com/rust-lang/rust-clippy/issues/702
@@ -6,7 +6,7 @@
 #![allow(clippy::all)]
 
 #![allow(unused_attributes)]
-#![rustfmt::skip]
+#![cfg_attr(rustfmt, rustfmt::skip)]
 
 #![allow(box_pointers)]
 #![allow(dead_code)]