Update Android.bp by running cargo_embargo

Test: ran cargo_embargo
Change-Id: Ie910f1b5a6ae992a334902ab75463290a8e4754b
diff --git a/Android.bp b/Android.bp
index c7f866d..48a4d85 100644
--- a/Android.bp
+++ b/Android.bp
@@ -40,7 +40,7 @@
     crate_name: "grpc_rust_plugin",
     cargo_env_compat: true,
     cargo_pkg_version: "0.12.1",
-    srcs: ["src/bin/grpc_rust_plugin.rs"],
+    crate_root: "src/bin/grpc_rust_plugin.rs",
     edition: "2018",
     features: [
         "default",
@@ -58,7 +58,7 @@
     crate_name: "grpcio_compiler",
     cargo_env_compat: true,
     cargo_pkg_version: "0.12.1",
-    srcs: ["src/lib.rs"],
+    crate_root: "src/lib.rs",
     test_suites: ["general-tests"],
     auto_gen_config: true,
     test_options: {
@@ -78,7 +78,7 @@
     crate_name: "grpcio_compiler",
     cargo_env_compat: true,
     cargo_pkg_version: "0.12.1",
-    srcs: ["src/lib.rs"],
+    crate_root: "src/lib.rs",
     edition: "2018",
     features: [
         "default",