Add SameSite=Lax rule to js cookie

Change-Id: I400a30b31de10cdfd5e4702772c5df2c60158137
diff --git a/dev/js/src/session.js b/dev/js/src/session.js
index 92bbadf..4a5c55a 100644
--- a/dev/js/src/session.js
+++ b/dev/js/src/session.js
@@ -63,7 +63,7 @@
       var date = new Date();
       date.setYear(date.getFullYear() + 1);
     */
-    return this._name + '=' + encodeURIComponent(JSON.stringify(this._hash)) + ';';
+    return this._name + '=' + encodeURIComponent(JSON.stringify(this._hash)) + ';SameSite=Lax';
   },