Fix annotation capitalisation

This was causing the following error:
[Doctrine\Common\Annotations\AnnotationException]                                                                                                                                        
[Semantical Error] The annotation "@Doctrine\ORM\Mapping\HasLifeCycleCallbacks" in class Lexik\Bundle\MailerBundle\Entity\EmailTranslation does not exist, or could not be auto-loaded.
Merge pull request #15 from achernev/patch-1

Fix annotation capitalisation