Change Middlewares to Middleware

[Temepest74]

I think this \Spatie\Permission\Middlewares\RoleMiddleware should be changed to this \Spatie\Permission\Middleware\RoleMiddleware. Laravel uses at his core "Middleware"

[erikn69]

That is an unnecessary breaking change, we would have to change our $routeMiddleware and $middlewarePriority
Maybe for the V5 version with upgrade guide