0.8.1

• Fixed deprecation message in Symfony: 'Method "Symfony\Component\Config\Definition\ConfigurationInterface::getConfigTreeBuilder()" might add "TreeBuilder" as a native return type declaration in the future. Do the same in implementation "Dubture\FFmpegBundle\DependencyInjection\Configuration" now to avoid errors or add an explicit @return annotation to suppress this message.'
• Fixed errors in test classes about method declarations not compatible with parents