[BUG] [SPRING-CLOUD] Spring-cloud generator adding @RequestParam instead of @RequestPart for mutilpart/form-data

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

Spring-cloud generator(feign client) adding @RequestParam instead of @RequestPart for MultipartFile

openapi-generator version

4.3.0

OpenAPI declaration file content or url

{
  "/endpoint": {
    "put": {
      "tags": [
        "MarksheetController"
      ],
      "operationId": "updateMarksheet",
      "parameters": [
        {
          "name": "studentId",
          "in": "path",
          "required": true,
          "schema": {
            "type": "number"
          }
        },
        {
          "name": "requestId",
          "in": "path",
          "required": true,
          "schema": {
            "type": "string"
          }
        }
      ],
      "requestBody": {
        "content": {
          "multipart/form-data": {
            "schema": {
              "type": "object",
              "properties": {
                "time": {
                  "type": "string"
                },
                "marksheet": {
                  "type": "string",
                  "format": "binary"
                }
              }
            }
          }
        }
      },
      "responses": {
        "200": {
          "description": "default response",
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/UpdateMarksheetResponse"
              }
            }
          }
        }
      }
    }
  }
}

Generated Code

ResponseEntity <UpdateMarksheetResponse> updateMarksheet(
    @ApiParam(value ="",required = true) @PathVariable("studentId") BigDecimal accountID, 
    @ApiParam(value = "", required = true) @PathVariable("requestId") String requestId, 
    @ApiParam(value = "") @RequestParam(value = "time", required = false) String time, 
    @ApiParam(value = "") @RequestParam("marksheet") MultipartFile marksheet
);

Command line used for generation

Generated using gradle task.

generatorName = "spring"
library = "spring-cloud"
configOptions = [
        "dateLibrary"              : "java-8",
        "serializationLibrary"     : "jackson",
        "useBeanValidation"        : "false"
]

Suggest a fix

Generate @RequestPart instead of @RequestParam , may require changes in template.

Start with the spring generator's spring-cloud library and compare the generated updateMarksheet method with the supplied multipart/form-data declaration and output. Trace the template or generation entry point responsible for MultipartFile parameters, then verify that multipart fields use @RequestPart rather than @RequestParam.