statements around created need to be updated

[aljones15]

Latest text as of 03/29/2024 is:

created
The date and time the proof was created is OPTIONAL and, if included, MUST be specified as an [[XMLSCHEMA11-2](https://www.w3.org/TR/vc-data-integrity/#bib-xmlschema11-2)] dateTimeStamp string, either in Universal Coordinated Time (UTC), denoted by a Z at the end of the value, or with a time zone offset relative to UTC. Time values that are incorrectly serialized without an offset MUST be interpreted as UTC.

(proof.created) if included, MUST be specified as an [XMLSCHEMA11-2] dateTimeStamp string, either in Universal Coordinated Time (UTC), denoted by a Z at the end of the value, or with a time zone offset relative to UTC.

(proof.created) Time values that are incorrectly serialized without an offset MUST be interpreted as UTC.

• this is probably a new test and can definitely wait, would require an incorrectly serialized created that would result in an error.