remove cookie on logout

auth.go

@@ -46,6 +46,7 @@ func logoutUser(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	http.SetCookie(w, &http.Cookie{Name: "wasmcloud-token", MaxAge: -1})
 	log.Printf("logout for %s", u.Username)
 	http.Redirect(w, r, "/login", http.StatusSeeOther)
 }