Update monolog compatibility

composer.json

@@ -18,7 +18,7 @@
     "require": {
         "php": ">=5.3.2",
         "doctrine/common": ">=2.1,<2.3-dev",
-        "monolog/monolog": ">=1.0,<1.2-dev",
+        "monolog/monolog": ">=1.0,<1.3-dev",
         "swiftmailer/swiftmailer": "4.2.*",
         "twig/twig": ">=1.1,<2.0-dev"
     },