Gets the requirements the document places on an interactive processor (Requirements, PDF 1.7); empty when none.
public IReadOnlyList<PdfRequirement> Requirements { get; }
ISO 32000-2 §7.7.2, Table 29, and §12.11. Exposed, never evaluated. An entry that is not an array of requirement dictionaries,
a requirement without its type or with a penalty outside 0 to 100, and handlers that are not dictionaries are reported as
RequirementInvalid when this property is read; elements that are not dictionaries are skipped.