Set Vary: Accept header for all responses (#398)

Author: reinink

src/Middleware.php

@@ -87,6 +87,8 @@ public function handle(Request $request, Closure $next)
 
         $response = $next($request);
 
+        $response->header('Vary', 'Accept');
+
         if (! $request->header('X-Inertia')) {
             return $response;
         }

src/Response.php

@@ -104,10 +104,7 @@ public function toResponse($request)
         ];
 
         if ($request->header('X-Inertia')) {
-            return new JsonResponse($page, 200, [
-                'Vary' => 'Accept',
-                'X-Inertia' => 'true',
-            ]);
+            return new JsonResponse($page, 200, ['X-Inertia' => 'true']);
         }
 
         return ResponseFactory::view($this->rootView, $this->viewData + ['page' => $page]);