Add return type declaration

[manzolo]

Suppress messages like: Method "Symfony\Component\Console\Command\Command::execute()" might add "int" as a native return type declaration in the future. Do the same in child class "FOS\JsRoutingBundle\Command\DumpCommand" now to avoid errors or add an explicit @return annotation to suppress this message. Method "Symfony\Component\Console\Command\Command::execute()" might add "int" as a native return type declaration in the future. Do the same in child class "FOS\JsRoutingBundle\Command\RouterDebugExposedCommand" now to avoid errors or add an explicit @return annotation to suppress this message.

[manzolo]

Travis for php 7.4 fail for indirect deprecation notices : 1x: Method "FilterIterator::accept()" might add "bool" as a native return type declaration in the future. Do the same in child class "SebastianBergmann\FileIterator\Iterator" now to avoid errors or add an explicit @return annotation to suppress this message.

1x in DumpCommandTest::testExecute from FOS\JsRoutingBundle\Tests\Command

[thePanz]

IMHO this is covered in #408

[manzolo]

covered in #408