遇到错误SameSite:http.SameSiteLaxMode

Trying to compile the following (github.com/alexedwards/scs) from source but I keep getting an error and don't understand what Im doing wrong

The error is as follows...

go/src/github.com/alexedwards/scs/session.go:69:11: undefined: http.SameSite

I have edited mine like this

Cookie: SessionCookie{ Name: "session", Domain: "my domain name", HttpOnly: true, Path: "/", Persist: true, Secure: false, SameSite: http.SameSiteLaxMode,