date-time field must mention RFC 3339 #220

Problem description
code/API_definitions/webrtc-call-handling.yaml:705:19 (LocationDetails) — [S-028] Property with format 'date-time' must have a description mentioning RFC\s3339
code/API_definitions/webrtc-events-subscriptions.yaml:1185:19 (LocationDetails) — [S-028] Property with format 'date-time' must have a description mentioning RFC\s3339

Expected behavior

description: Timestamp. It must follow [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339#section-5.6) and must have time zone.

Additional context
https://github.com/camaraproject/Commonalities/blob/32b878daa2bcb253abf91c36daa5c8b88b5cb5fe/artifacts/common/CAMARA_common.yaml#L95-L99