Upgrade rust/crates/protobuf-codegen to 2.22.1

Test: make
Change-Id: Ib964aed5462ba84bba67f2dec07b2ff127ae63c2
diff --git a/Android.bp b/Android.bp
index 620d9f7..e180529 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,4 +1,5 @@
 // This file is generated by cargo2android.py --run --dependencies --tests.
+// Do not modify this file as changes will be overridden on upgrade.
 
 package {
     default_applicable_licenses: [
@@ -21,7 +22,6 @@
 
 rust_library_host {
     name: "libprotobuf_codegen",
-    // has rustc warnings
     crate_name: "protobuf_codegen",
     srcs: ["src/lib.rs"],
     edition: "2015",
@@ -32,11 +32,13 @@
 
 rust_test_host {
     name: "protobuf-codegen_host_test_src_lib",
-    // has rustc warnings
     crate_name: "protobuf_codegen",
     srcs: ["src/lib.rs"],
     test_suites: ["general-tests"],
     auto_gen_config: true,
+    test_options: {
+        unit_test: true,
+    },
     edition: "2015",
     rustlibs: [
         "libprotobuf",
@@ -45,7 +47,6 @@
 
 rust_binary_host {
     name: "protoc-gen-rust",
-    // has rustc warnings
     crate_name: "protoc_gen_rust",
     srcs: ["src/bin/protoc-gen-rust.rs"],
     edition: "2015",
@@ -56,4 +57,4 @@
 }
 
 // dependent_library ["feature_list"]
-//   protobuf-2.20.0
+//   protobuf-2.22.1