Openapi 3.0.X support for shcemas in paramters in marshmallow extension

[fMeow]

Currently, marshmallow extension only partially supports openapi 3.0.X . In my case, I would like to assign marshmallow schema object in parameters.

The code below is a demonstration for my case.

from marshmallow import Schema, fields

class PetSchema(Schema):
    id = fields.Int(dump_only=True)
    name = fields.Str()
    age = fields.Int()

def pet_view():
    """Not much to see here.
    ---
    get:
        parameters:
            - in: query
              schema: PetSchema
    """
    return '...'

The expected result in Openapi Specification 3.0.X is as below:

get:
  parameters:
  - in: query
    name: name
    required: false
    schema: 
      type: string
  - in: query
    name: age
    required: false
    schema: 
      format: int32
      type: integer

In short, format and type field must be inside schema object. A parameter object do not allow format field nor type field.

However, current result is as follow:

get:
  parameters:
  - in: query
    name: name
    required: false
    type: string
  - in: query
    name: age
    required: false
    format: int32
    type: integer

Thus, I modify the code to fix this behavior. Also, I notice that collectionFormat field is now deprecated in Openapi 3.0.X . Instead, an equivalent of collection set to multi is that style set to form, with explode set to true.
See style values. Below is some important description or examples copied directly from openapi specification.

style	explode	empty	string	array	object
form	true	color=	color=blue	color=blue&color=black&color=brown	R=100&G=200&B=150

name: id
in: query
description: ID of the object to fetch
required: false
schema:
  type: array
  items:
    type: string
style: form
explode: true

[sloria]

This looks great. Thanks!