Exit early for `304`

lib/alias.js

@@ -59,6 +59,8 @@ export default class Alias extends Now {
         body: { alias }
       });
 
+      if (304 === res.status) return;
+
       const body = await res.json();
       if (this._debug) console.timeEnd(`> [debug] /now/deployments/${depl.uid}/aliases #${attempt}`);