Remove DI\InvokerInterface (in favor of Invoker\InvokerInterface) #516
Description
Invoker\InvokerInterface exists since version 5 and is defined in the PHP-DI/Invoker package.
The DI\InvokerInterface is useless, it's empty and extends Invoker\InvokerInterface.
Removing it is like removing DI\ContainerInterface in favor of PSR-11 or container-interop for example (until there's a PSR for invokers…).