rust_proto: use protobuf crate version 2.x

Test: build
Bug: 270895633
Change-Id: I04e5e7fe70b8c509cd1b35852b75a0f24a633ce9
diff --git a/rust/testing.go b/rust/testing.go
index 24ca3d6..a33d948 100644
--- a/rust/testing.go
+++ b/rust/testing.go
@@ -127,7 +127,7 @@
 			min_sdk_version: "29",
 		}
 		rust_library {
-			name: "libprotobuf",
+			name: "libprotobuf_deprecated",
 			crate_name: "protobuf",
 			srcs: ["foo.rs"],
 			host_supported: true,