Merge branch '5.1'

* 5.1:
  simple_preauth was removed in symfony 5.0
  Fixed a PHPUnit deprecation

Author: javiereguiluz

reference/configuration/security.rst

@@ -395,8 +395,6 @@ depend on the authentication mechanism, which can be any of these:
                         # ...
                     remote_user:
                         # ...
-                    simple_preauth:
-                        # ...
                     guard:
                         # ...
                     form_login:
@@ -405,8 +403,6 @@ depend on the authentication mechanism, which can be any of these:
                         # ...
                     json_login:
                         # ...
-                    simple_form:
-                        # ...
                     http_basic:
                         # ...
                     http_basic_ldap: