Merge branch '3.4' into 4.3

* 3.4:
  [Validator] Allow underscore character "_" in URL username and password
  [SecurityBundle] Passwords are not encoded when algorithm set to \"true\"
  do not validate passwords when the hash is null
  [DI] Fix making the container path-independent when the app is in /app
  Allow copy instead of symlink for ./link script
  [FrameworkBundle] resolve service locators in `debug:*` commands
  bumped Symfony version to 3.4.37
  updated VERSION for 3.4.36
  update CONTRIBUTORS for 3.4.36
  updated CHANGELOG for 3.4.36

Author: xabbuh

Constraints/UrlValidator.php

@@ -24,7 +24,7 @@ class UrlValidator extends ConstraintValidator
 {
     const PATTERN = '~^
             (%s)://                                 # protocol
-            (([\.\pL\pN-]+:)?([\.\pL\pN-]+)@)?      # basic auth
+            (([\_\.\pL\pN-]+:)?([\_\.\pL\pN-]+)@)?  # basic auth
             (
                 ([\pL\pN\pS\-\_\.])+(\.?([\pL\pN]|xn\-\-[\pL\pN-]+)+\.?) # a domain name
                     |                                                 # or

Tests/Constraints/UrlValidatorTest.php

@@ -152,9 +152,11 @@ public function getValidUrls()
             ['http://☎.com/'],
             ['http://username:password@symfony.com'],
             ['http://user.name:password@symfony.com'],
+            ['http://user_name:pass_word@symfony.com'],
             ['http://username:pass.word@symfony.com'],
             ['http://user.name:pass.word@symfony.com'],
             ['http://user-name@symfony.com'],
+            ['http://user_name@symfony.com'],
             ['http://symfony.com?'],
             ['http://symfony.com?query=1'],
             ['http://symfony.com/?query=1'],