Decode a CBOR (Concise Binary Object Representation) data stream represented by a List<int>.
The method decodes the CBOR data and returns the resulting CborObject.
Parse a datetime string in RFC3339 format and return a corresponding DateTime object.
The method checks if the input string contains a timezone offset. If it does, it splits the string
into date and offset parts, parses the date part, and returns it. If there's no offset, it parses
the input string as a UTC time.