protected function configure()
{
    $this->setName('ez:support:update_type')
        ->setDefinition(
            array(
                new InputArgument('contentType', InputArgument::REQUIRED, 'Content type to update'),
            )
        )
        ->setDescription('Updates a content type');
}

protected function execute(InputInterface $input, OutputInterface $output)
{
    $repository = $this->getContainer()->get('ezpublish.api.repository');
    // set admin as current user
    $user = $repository->getUserService()->loadUser( 14 );
    $repository->setCurrentUser( $user );
    /** @var \eZ\Publish\API\Repository\ContentTypeService $contentTypeService */
    $contentTypeService = $repository->getContentTypeService();
    $contentType = $contentTypeService->loadContentTypeByIdentifier(
        $input->getArgument('contentType')
    );
    $contentTypeDraft = $contentTypeService->createContentTypeDraft($contentType);
    $contentTypeUpdateStruct = $contentTypeService->newContentTypeUpdateStruct();
    $contentTypeUpdateStruct->mainLanguageCode = 'eng-GB';
    $contentTypeService->updateContentTypeDraft($contentTypeDraft, $contentTypeUpdateStruct);
    $contentTypeService->publishContentTypeDraft($contentTypeDraft);
}