Mark service as public explicitly

Symfony 4.0 will make services private by default, so this needs to be
configured explicitly.

Author: stof

src/DependencyInjection/KeenIOExtension.php

@@ -24,6 +24,7 @@ public function load(array $configs, ContainerBuilder $container)
         $container->setParameter('keen_io_factory.class', 'KeenIO\\Client\\KeenIOClient');
 
         $definition = new Definition('%keen_io.class%', array($arguments));
+        $definition->setPublic(true);
 
         if (method_exists($definition, 'setFactory')) {
             $definition->setFactory(array('%keen_io_factory.class%', 'factory'));