Change 301 redirect to 302 redirect

Change the 301 (permanent) redirect to 302 (temporary) redirect in
LinkController.php. This is because the 301 redirect is cached by
browsers which leads to issues when link are updated/deleted. The links
should be 302 as the long link can change and nowadays the overhead of
a 302 redirect is minimal.

app/Http/Controllers/LinkController.php

@@ -107,7 +107,7 @@ public function performRedirect(Request $request, $short_url, $secret_key=false)
             ]);
         }
         else{
-            return redirect()->to($long_url, 301);
+            return redirect()->to($long_url, 302);
         }
     }