Update to FOSUserBundle 3.1

Also remove some deprecation from Symfony.
Use `LegacyEventDispatcherProxy` to handle Symfony 4 dispatch from FOSUser

app/config/config.yml

@@ -179,8 +179,10 @@ fos_user:
         confirmation:
             enabled: "%fosuser_confirmation%"
     from_email:
-        address:        "%from_email%"
-        sender_name:    wallabag
+        address: "%from_email%"
+        sender_name: wallabag
+    service:
+        mailer: fos_user.mailer.twig_swift
 
 fos_oauth_server:
     db_driver:           orm

app/config/security.yml

@@ -34,12 +34,10 @@ security:
             provider: fos_userbundle
 
         login_firewall:
-            logout_on_user_change: true
             pattern: ^/login$
             anonymous:  ~
 
         secured_area:
-            logout_on_user_change: true
             pattern: ^/
             form_login:
                 provider: fos_userbundle