Update monolog compatibility

Author: Seldaek

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"
  },