Upgrade rust/crates/protobuf-codegen to 2.18.0

* Revert local change, remove patches/*.diff
* Add echo version in post_update.sh

Bug: 170256643
Test: atest -c --include-subdirs external/rust/crates
Test: atest -c --host --include-subdirs external/crosvm
Change-Id: I701b9b2a36f6e8e2ec0a37f47fe85cbb68f2866b
diff --git a/src/code_writer.rs b/src/code_writer.rs
index 855b785..8b53bc6 100644
--- a/src/code_writer.rs
+++ b/src/code_writer.rs
@@ -58,8 +58,7 @@
         self.write_line("#![allow(clippy::all)]");
         self.write_line("");
         self.write_line("#![allow(unused_attributes)]");
-        // ANDROID CHANGE: comment out rustfmt::skip to fix compilation error.
-        //self.write_line("#![rustfmt::skip]");
+        self.write_line("#![rustfmt::skip]");
         self.write_line("");
         self.write_line("#![allow(box_pointers)]");
         self.write_line("#![allow(dead_code)]");