Validate HTTP requests and responses against an OpenAPI v3.1 document

Changes for 0.048 - 2023-10-04T05:34:44Z

• now validating all headers of a given name, not just the first, when provided on the request/response as separate lines
• multiple headers of the same name can be validated as an array or object as per deserialization rules in the OpenAPI v3.1 specification.