Exit on SIGTERM

we currently only listen for SIGINT while k8s sends
a SIGTERM to shutdown a process, so we need to listen for that
too

src/runner.rs

@@ -61,11 +61,26 @@ pub async fn run_with_config(
         .validate()?
         .build();
 
+    #[cfg(target_os = "linux")]
+    let mut sig_term_fut = signal::unix::signal(signal::unix::SignalKind::terminate())?;
+    #[cfg(not(target_os = "linux"))]
+    let sig_term = std::future::pending();
+
     let (shutdown_tx, shutdown_rx) = watch::channel::<()>(());
+    let signal_log = log.clone();
     tokio::spawn(async move {
+        #[cfg(target_os = "linux")]
+        let sig_term = sig_term_fut.recv();
+        tokio::select! {
+            _ = signal::ctrl_c() => {
+                info!(signal_log, "Received SIGINT")
+            }
+            _ = sig_term => {
+                info!(signal_log, "Received SIGTERM")
+            }
+        }
         // Don't unwrap in order to ensure that we execute
         // any subsequent shutdown tasks.
-        signal::ctrl_c().await.ok();
         shutdown_tx.send(()).ok();
     });