fix(validator): allow header deserialization

[oliviersorine]

This PR allows us to provide better header validation on complex header.

For header value which can be like "key1=value1,key2=value", it will be deserialize into

[
  "key1" => "value1",
  "key2" => "value2"
]

and then be correctly match with openapi declaration like:

    - name: Pagination
      in: header
      required: true
      style: simple
      explode: true
      schema:
        type: object
        required:
          - key1
          - key2
        properties:
          key1:
            type: integer
            example: 1
          key2:
            type: integer
            example: 10

Please note, part of the forked lib seems weird at first glance since some validators wait for array to check object type.
I will continue to look for more information as soon as possible.

[DotnDev]

🥳