Update deps
Update deps

Changelogs summary:

 - phpunit/php-code-coverage updated from 3.0.1 to 3.0.2
   See changes: https://github.com/sebastianbergmann/php-code-coverage/compare/3.0.1...3.0.2
   Release notes: https://github.com/sebastianbergmann/php-code-coverage/releases/tag/3.0.2

 - symfony/symfony updated from 2.8.x-dev to 2.8.x-dev
   See changes: https://github.com/symfony/symfony/compare/cbaa9c4...fef28b2

jolicode/slack-secret-santa,jolicode/slack-secret-santa,jolicode/slack-secret-santa