Fixed the dockerfile when the composer autoload config is empty

Author: gplanchat

src/Service.php

@@ -14,9 +14,9 @@
         'ext-pdo',
     ],
     steps: [
-        "extractor" => "extractor",
-        "lookup" => "transformer",
-        "loader" => "loader",
+        new Configurator\Pipeline\StepExtractor(),
+        new Configurator\Pipeline\StepTransformer('lookup'),
+        new Configurator\Pipeline\StepLoader(),
     ],
 )]
 final class Service implements Configurator\PipelinePluginInterface