✨ Proposal: date-time format to accept those in RFC 9557

[tisonkun]

Describe the inspiration for your proposal

Currently, the "date-time" format with string type only accepts timestamp strings in RFC 3339 format. RFC 9557 is an update to RFC 3339. We may accept timestamp strings in RFC 9557 format also.

Describe the proposal

As trivial as in the inspiration. Refer to https://www.rfc-editor.org/rfc/rfc9557.html.

Describe alternatives you've considered

No response

Additional context

I encountered this issue while implementing GREsau/schemars#364, where I tried to integrate an RFC 9557 implementation with JSON Schema definitions.