[BUG] Python client fails for camelCase multipart/form-data file binary property

Created by: alejogun

Bug Report Checklist

Have you provided a full/minimal spec to reproduce the issue?
Have you validated the input using an OpenAPI validator (example)?
Have you tested with the latest master to confirm the issue still exists?
Have you searched for related issues/PRs?
What's the actual output vs expected output?
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Description

When generating the Python client code for the OAS YAML spec provided below, there's a mapping error in the generated code for the camelCase property inputFile of binary type:

The code is assigning params['file'][param_name] (param_name = 'input_file'), when it should be params['file'][base_name] (base_name = 'inputFile')

Generated code looks like:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][param_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][param_name] = param_value

It should be:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][base_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][base_name] = param_value

openapi-generator version

5.2.0

OpenAPI declaration file content or URL

minimal-api-spec.yaml (click expand to visualize them)

openapi: 3.0.1
info:
  title: My API
  version: 0.9.0

paths:
  /uploadFile:
    post:
      operationId: uploadFile
      requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                description:
                  type: string
                inputFile:
                  type: string
                  format: binary
              required:
                - description
                - inputFile
      responses:
        '201':
          description: Created

Generation Details

openapi-generator generate \
  --input-spec minimal-api-spec.yaml \
  --generator-name python \
  --package-name client \
  --output client

Steps to reproduce

Generate the Python client code with the command above
Verify the generated api_client.py has the wrong mapping for the 'file' params