add basic version command to shim

Signed-off-by: Rajat Jindal <[email protected]>

containerd-shim-spin/src/main.rs

@@ -3,10 +3,18 @@ use containerd_shim_wasm::{
     container::Instance,
     sandbox::cli::{revision, shim_main, version},
 };
+use std::env;
 
 mod engine;
+mod version;
 
 fn main() {
+    let args: Vec<String> = env::args().collect();
+    if args.len() > 1 && args[1] == "--version" {
+        version::print_version();
+        return;
+    }
+
     // Configure the shim to have only error level logging for performance improvements.
     let shim_config = Config {
         default_log_level: "error".to_string(),

containerd-shim-spin/src/version.rs

@@ -0,0 +1,5 @@
+const VERSION: &'static str = env!("CARGO_PKG_VERSION");
+
+pub fn print_version() {
+    println!("{}", VERSION);
+}