Fixes typo on Doctrine lifecycle event (PreUpdate)

Avoids this error message when I use doctrine fixtures command:

    [Doctrine\Common\Annotations\AnnotationException]                                                                                                                                       
    [Semantical Error] The annotation "@Doctrine\ORM\Mapping\preUpdate" in method Google\GeolocationBundle\Entity\Location::setUpdatedValue() does not exist, or could not be auto-loaded.