Merge branch '7.1' into 7.2

* 7.1:
  [HttpClient] Close gracefull when the server closes the connection abruptly
  ensure that tests are run with lowest supported Serializer versions
  read runtime config from composer.json in debug dotenv command

Author: nicolas-grekas

Response/CurlResponse.php

@@ -323,7 +323,7 @@ private static function perform(ClientState $multi, ?array &$responses = null):
                 }
 
                 $multi->handlesActivity[$id][] = null;
-                $multi->handlesActivity[$id][] = \in_array($result, [\CURLE_OK, \CURLE_TOO_MANY_REDIRECTS], true) || '_0' === $waitFor || curl_getinfo($ch, \CURLINFO_SIZE_DOWNLOAD) === curl_getinfo($ch, \CURLINFO_CONTENT_LENGTH_DOWNLOAD) ? null : new TransportException(ucfirst(curl_error($ch) ?: curl_strerror($result)).\sprintf(' for "%s".', curl_getinfo($ch, \CURLINFO_EFFECTIVE_URL)));
+                $multi->handlesActivity[$id][] = \in_array($result, [\CURLE_OK, \CURLE_TOO_MANY_REDIRECTS], true) || '_0' === $waitFor || curl_getinfo($ch, \CURLINFO_SIZE_DOWNLOAD) === curl_getinfo($ch, \CURLINFO_CONTENT_LENGTH_DOWNLOAD) || (curl_error($ch) === 'OpenSSL SSL_read: SSL_ERROR_SYSCALL, errno 0' && -1.0 === curl_getinfo($ch, \CURLINFO_CONTENT_LENGTH_DOWNLOAD) && \in_array('close', array_map('strtolower', $responses[$id]->headers['connection']), true)) ? null : new TransportException(ucfirst(curl_error($ch) ?: curl_strerror($result)).\sprintf(' for "%s".', curl_getinfo($ch, \CURLINFO_EFFECTIVE_URL)));
             }
         } finally {
             $multi->performing = false;