Compatibility with ``echo/v4``

[kevincobain2000]

Hi

cannot use echosession.New() (type "github.com/labstack/echo".MiddlewareFunc) as type 
"github.com/labstack/echo/v4".MiddlewareFunc in argument to e.Use

Any plans to upgrade reference for echo/v4 compatibility?
https://github.com/go-session/echo-session/blob/master/session.go#L5