Ensure UriInterface is cast to string in Redirect

- Casts the `$uri` argument to a string when creating the `Location` header.

Author: weierophinney

src/Response/RedirectResponse.php

@@ -41,7 +41,7 @@ public function __construct($uri, $status = 302, array $headers = [])
             ));
         }
 
-        $headers['location'] = [$uri];
+        $headers['location'] = [(string) $uri];
         parent::__construct('php://temp', $status, $headers);
     }
 }