Vendor dependencies for 0.3.0 release

vendor/wasip2/examples/cli-command.rs

@@ -0,0 +1,14 @@
+use std::io::Write as _;
+
+wasip2::cli::command::export!(Example);
+
+struct Example;
+
+impl wasip2::exports::cli::run::Guest for Example {
+    fn run() -> Result<(), ()> {
+        let mut stdout = wasip2::cli::stdout::get_stdout();
+        stdout.write_all(b"Hello, WASI!").unwrap();
+        stdout.flush().unwrap();
+        Ok(())
+    }
+}