Merge branch '6.3' into 6.4

* 6.3:
  fix merge
  do not detect the deserialization_path context value twice
  fix detecting the database server version
  [Cache] Add url decoding of password in `RedisTrait` DSN
  [Serializer] Remove incompatible type declaration with PHP 7.2
  [Serializer] Fix test
  Fix denormalizing empty string into object|null parameter
  [PropertyInfo] Fixed promoted property type detection for `PhpStanExtractor`
  [Serializer] Move discrimination to abstract
  [Serializer] Fix deserialization_path missing using contructor
  [Serializer] Fix access to private when Ignore
  [HttpKernel] Fix logging deprecations to the "php" channel when channel "deprecation" is not defined
  Fix message handlers with multiple from_transports
  fix detecting the server version with Doctrine DBAL 4
  [Serializer] Fix constructor deserialization path
  [Serializer] Fix XML attributes not added on empty

Author: xabbuh

Resources/config/debug_prod.php

@@ -27,7 +27,7 @@
                 param('debug.error_handler.throw_at'),
                 param('kernel.debug'),
                 param('kernel.debug'),
-                service('logger')->nullOnInvalid(),
+                null, // Deprecation logger if different from the one above
             ])
             ->tag('monolog.logger', ['channel' => 'php'])