erp5_core: Use SameSite=Lax cookie

SameSite=None breaks the compatibility with some browser versions.
https://www.chromium.org/updates/same-site/incompatible-clients

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_auto_logout/setAuthCookie.py

@@ -21,6 +21,6 @@ resp.setCookie(
   path='/',
   secure=getattr(portal, 'REQUEST', {}).get('SERVER_URL', '').startswith('https:'),
   http_only=True,
-  same_site='None',
+  same_site='Lax',
   **kw
 )