[FrameworkBundle] Use an array for exclude directive

symfony/framework-bundle/4.2/config/services.yaml

@@ -15,7 +15,11 @@ services:
     # this creates a service per class whose id is the fully-qualified class name
     App\:
         resource: '../src/*'
-        exclude: '../src/{DependencyInjection,Entity,Tests,Kernel.php}'
+        exclude:
+            - '../src/DependencyInjection/'
+            - '../src/Entity/'
+            - '../src/Kernel.php'
+            - '../src/Tests/'
 
     # controllers are imported separately to make sure services can be injected
     # as action arguments even if you don't extend any base controller class