Add "none" to supported same site options in session config (#5174)

config/session.php

@@ -190,7 +190,7 @@ return [
     | take place, and can be used to mitigate CSRF attacks. By default, we
     | do not enable this as other CSRF protection services are in place.
     |
-    | Supported: "lax", "strict"
+    | Supported: "lax", "strict", "none"
     |
     */