@node-saml/node-saml's validatePostRequestAsync does not include checkTimestampsValidityError

Node-SAML is a SAML library not dependent on any frameworks that runs in Node. The lack of checking of current timestamp allows a LogoutRequest XML to be reused multiple times even when the current time is past the NotOnOrAfter. This could impact the user where they would be logged out from an expired LogoutRequest. In bigger contexts, if LogoutRequests are sent out in mass to different SPs, this could impact many users on a large scale. This issue was patched in version 4.0.5.