Merge branch '6.4' into 7.0

* 6.4: (28 commits)
  [Serializer] Fix `@method` annotation
  fix compatibility with Doctrine DBAL 4
  ensure string type with mbstring func overloading enabled
  [HttpKernel] Fix quotes expectations in tests
  [Validator] updated Greek translation
  [Cache][HttpFoundation][Lock] Fix empty username/password for PDO PostgreSQL
  [HttpClient][WebProfilerBundle] Do not generate cURL command when files are uploaded
  render newline in front of all script elements
  fix test fixture
  fix tests
  [Cache] Fix property types in PdoAdapter
  PHP files cannot be executable without shebang
  [TwigBridge] Mark CodeExtension as @internal
  Remove full DSNs from exception messages
  [Yaml] Fix uid binary parsing
  Disable the "Copy as cURL" button when the debug info are disabled
  [HttpClient] Replace `escapeshellarg` to prevent overpassing `ARG_MAX`
  Fix missing `profile` option for console commands
  [HttpFoundation][Lock] Makes MongoDB adapters usable with `ext-mongodb` only
  [HttpKernel] Preventing error 500 when function putenv is disabled
  ...

DependencyInjection/DebugExtension.php

@@ -20,7 +20,6 @@
 use Symfony\Component\DependencyInjection\Loader\PhpFileLoader;
 use Symfony\Component\DependencyInjection\Reference;
 use Symfony\Component\VarDumper\Caster\ReflectionCaster;
-use Symfony\Component\VarDumper\Dumper\HtmlDumper;
 
 /**
  * @author Nicolas Grekas <p@tchwork.com>