Add getProjectDir method to Kernel

This allows prod mode to find the project dir without the reference to
the composer.json file. This file is not present in prod mode

src/Kernel.php

@@ -19,9 +19,13 @@
 
 use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
 use Symfony\Component\HttpKernel\Kernel as BaseKernel;
-use Symfony\Component\Routing\RouteCollectionBuilder;
 
 class Kernel extends BaseKernel
 {
     use MicroKernelTrait;
+
+    public function getProjectDir(): string
+    {
+        return dirname(__DIR__, 1);
+    }
 }