Fix "!event" deprecation

Author: dunglas

app/config/config_dev.yml

@@ -17,10 +17,10 @@ monolog:
             type: stream
             path: "%kernel.logs_dir%/%kernel.environment%.log"
             level: debug
-            channels: [!event]
+            channels: ["!event"]
         console:
             type:   console
-            channels: [!event, !doctrine, !console]
+            channels: ["!event", "!doctrine", "!console"]
         # uncomment to get logging in your browser
         # you may have to allow bigger header sizes in your Web server configuration
         #firephp:
@@ -31,4 +31,4 @@ monolog:
         #    level:  info
 
 #swiftmailer:
-#    delivery_addresses: ['me@example.com']
+#    delivery_addresses: ["me@example.com"]