Merge branch '4.3' into 4.4

* 4.3:
  [FWBundle] Remove unused parameter
  [Intl] [Workflow] fixes English grammar typos
  [Filesystem] [Serializer] fixes English grammar typo
  [Messenger] Adding exception to amqp transport in case amqp ext is not installed
  [Monolog Bridge] Fixed accessing static property as non static.
  Improve Symfony description
  Add DateTimeZoneNormalizer into Dependency Injection
  [Messenger] Error when specified default bus is not among the configured
  [Validator] Add Japanese translation
  [Workflow] Apply the same logic of precedence between the apply() and the buildTransitionBlockerList() method
  Remove some unused methods parameters
  Avoid empty \"If-Modified-Since\" header in validation request
  [Security] Fix SwitchUser is broken when the User Provider always returns a valid user
  Fix error message according to the new regex
  compatibility with DoctrineBundle 2
  [Validator] ConstraintValidatorTestCase: add missing return value to mocked validate method calls

Author: Robin Chalas

ButtonBuilder.php

@@ -63,7 +63,7 @@ public function __construct(?string $name, array $options = [])
 
         if (preg_match('/^([^a-zA-Z0-9_].*)?(.*[^a-zA-Z0-9_\-:].*)?$/D', $name, $matches)) {
             if (isset($matches[1])) {
-                @trigger_error(sprintf('Using names for buttons that do not start with a lowercase letter, a digit, or an underscore is deprecated since Symfony 4.3 and will throw an exception in 5.0 ("%s" given).', $name), E_USER_DEPRECATED);
+                @trigger_error(sprintf('Using names for buttons that do not start with a letter, a digit, or an underscore is deprecated since Symfony 4.3 and will throw an exception in 5.0 ("%s" given).', $name), E_USER_DEPRECATED);
             }
             if (isset($matches[2])) {
                 @trigger_error(sprintf('Using names for buttons that do not contain only letters, digits, underscores ("_"), hyphens ("-") and colons (":") ("%s" given) is deprecated since Symfony 4.3 and will throw an exception in 5.0.', $name), E_USER_DEPRECATED);