feat: version number now includes Git commit short id

Signed-off-by: Lars Wirzenius <liw@liw.fi>

build.rs

@@ -21,6 +21,10 @@ fn main() {
         .unwrap_or_else(|| String::from("unknown"));
 
     println!("cargo:rustc-env=GIT_HEAD={hash}");
+    println!(
+        "cargo:rustc-env=VERSION={}@{hash}",
+        env!("CARGO_PKG_VERSION")
+    );
     println!("cargo:rustc-rerun-if-changed=.git/HEAD");
 
     if let Err(e) = subplot_build::codegen("ci-broker.subplot") {