Project is using old interface

[MathijsG]

Slim 3 changed the containerinterface from Interop to psr in later versions of Slim 3 (slimphp/Slim@305e2df).

See: https://stackoverflow.com/questions/37906363/slim-controller-issue-must-be-an-instance-of-containerinterface-instance-of-s

A solution is to alter ControllerAbstract.php and change:

use Interop\Container\ContainerInterface;

to:

use Psr\Container\ContainerInterface;

[ricardoper]

Fixed, Thanks @MathijsG.