chore: missing file

Author: alexeagle

examples/rust/BUILD.bazel

@@ -0,0 +1,18 @@
+load("@rules_rust//rust:defs.bzl", "rust_library_group")
+
+package(default_visibility = ["//tools/toolchains:__pkg__"])
+
+rust_library_group(
+    name = "prost_runtime",
+    deps = [
+        "@crates//:prost",
+    ],
+)
+
+rust_library_group(
+    name = "tonic_runtime",
+    deps = [
+        ":prost_runtime",
+        "@crates//:tonic",
+    ],
+)