Outdated Network layer protection guidance in CAEP Interoperability Profile 1.0

[2.1. Network layer protection](https://openid.github.io/sharedsignals/openid-caep-interoperability-profile-1_0.html#section-2.1) in CAEP Interoperability Profile references obsolete [RFC7525](https://www.rfc-editor.org/rfc/rfc7525.html) which has been superseded by [RFC9325](https://www.rfc-editor.org/rfc/rfc9325.html).