build: vendor Rust crate dependencies

src/machoke/BUILD

@@ -4,6 +4,7 @@ rust_library(
     name = "machoke_lib",
     crate_name = "machoke",
     srcs = ["lib.rs"],
+    deps = ["//third_party/crates:anyhow"],
 )
 
 rust_binary(

src/machoke/Cargo.lock

@@ -1,7 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-version = 4
-
-[[package]]
-name = "machoke"
-version = "0.1.0"

src/machoke/Cargo.toml

@@ -11,3 +11,4 @@ name = "machoke"
 path = "main.rs"
 
 [dependencies]
+anyhow = "1"

src/machoke/lib.rs

@@ -1,3 +1,5 @@
-pub fn greeting() -> &'static str {
-    "Hello from machoke"
+use anyhow::Result;
+
+pub fn greeting() -> Result<&'static str> {
+    Ok("Hello from machoke")
 }

src/machoke/main.rs

@@ -1,3 +1,6 @@
 fn main() {
-    println!("{}", machoke::greeting());
+    println!(
+        "{}",
+        machoke::greeting().expect("greeting should be available")
+    );
 }