Merge branch '6.2' into 6.3

* 6.2:
  [Serializer] Handle datetime deserialization in U format
  [HttpFoundation] Fix file streaming after connection aborted
  Update HeaderBag::all PhpDoc
  [Messenger] Add `IS_REPEATABLE` flag to `AsMessageHandler` attribute
  Allow resources in Query::setParam
  Fix param type annotation
  [HttpClient] Fix setting duplicate-name headers when redirecting with AmpHttpClient

Author: nicolas-grekas

Response/AmpResponse.php

@@ -346,7 +346,7 @@ private static function followRedirects(Request $originRequest, AmpClientState $
             }
 
             foreach ($originRequest->getRawHeaders() as [$name, $value]) {
-                $request->setHeader($name, $value);
+                $request->addHeader($name, $value);
             }
 
             if ($request->getUri()->getAuthority() !== $originRequest->getUri()->getAuthority()) {