5.1.0 format has inconsistent timestamp, wrong description, and lacks string format

[ostefano]

In the just released 5.1 schema, field timestamp is type string with an unspecified format (while 5.0 had format date-time). Is there a reason for this?

Also, timestamp description is actually wrong:

Date/time format based on RFC3339 and ISO ISO8601, with an optional timezone in the format 'yyyy-MM-ddTHH:mm:ss[+-]ZH:ZM'

While the regex (and actual timestamp values, see here for example https://raw.githubusercontent.com/CVEProject/cvelistV5/09b7c787c45c0193ce24c1fdcb98930c562741ef/cves/2024/31xxx/CVE-2024-31340.json) matches another format: yyyy-MM-ddTHH:mm:ss with optional Z or Z[+-]HH:mm (regex (Z|[+-][0-9]{2}:[0-9]{2})?).