Merge branch '5.0'

* 5.0:
  [Routing] fix tests
  [DI] minor cleanup
  [Form] group constraints when calling the validator
  Remove wrong @group legacy annotations
  [DependencyInjection] Fix dumping multiple deprecated aliases
  allow button names to start with uppercase letter
  Allow PHP ^7.2.5
  States that the HttpClient provides a Http Async implementation
  [Routing] Fix ContainerLoader and ObjectLoaderTest
  [HttpKernel] Make ErrorListener::onKernelException()'s dispatcher argument explicit
  [HttpKernel] Drop deprecated ExceptionListener
  Removed extra whitespace
  [Security] Fix best encoder not wired using migrate_from

composer.json

@@ -20,7 +20,7 @@
         }
     ],
     "require": {
-        "php": "^7.2.9"
+        "php": "^7.2.5"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\CssSelector\\": "" },