[Java] ApiResponse code contains string

Description

When using kotlin-spring generator and spring-boot library to generate controller, service, modles, etc. in controller's @ApiResponse, there is code 4XX (which is from docs of openAPI 3 definition of range of response codes). But in generated controller it is errorous because the code is of type int and not string. Will this behavior will be changed to generate wntire range of family codes or this will not be supported?

openapi-generator version

4.3.0

OpenAPI declaration file content or url

openapi: "3.0.2"
info:
  title: "Some API"
  version: "1.0.0"

paths: 
  /test/post:
    post:
      tags:
        - "tag1"
      summary: "Tag1 description"
      description: ""
      operationId: "someId"
      requestBody:
        content:
          application/json:
            schema:
              $ref: "path/to/requesting/object"
      responses:
        '200':
          description: |
            `OK`
          content:
            text/plain:
              schema:
                type: string
        '4XX':
          description: |
            General response to all 4XX error codes.
          content:
            application/json:
              schema:
                $ref: "path/to/responding/object"
        '5XX':
          description: |
            General response to all 5XX error codes.
          content:
            application/json:
              schema:
                $ref: "path/to/responding/object"

Command line used for generation

Gradle task was used like this:
task generateVectorAPIServer(type: org.openapitools.generator.gradle.plugin.tasks.GenerateTask) {
id = "generateAPIServer"
generatorName = "kotlin-spring"
inputSpec = "../some-api/api/openapi.yaml"
outputDir = "$buildDir/generated-src-swagger/main/kotlin".toString()
generateModelTests = false
generateApiTests = false
additionalProperties = [
library: "spring-boot",
beanValidations: "true",
swaggerAnnotations: "true",
apiPackage: "cz.some.rest.controller",
apiSuffix: "Controller",
modelPackage: "cz.some.model",
exceptionHandler: "true",
gradleBuildFile: "false",
serviceInterface: "true",
serviceImplementation: "false",
enumPropertyNaming: "UPPERCASE",
serializableModel: "true",
serializationLibrary: "jackson"

]

}

Steps to reproduce

Used provided yaml and gradle task to generate

Generated file exaple:

@ApiOperation(......)
    @ApiResponses(
        value = [ApiResponse(code = 200, message = "`OK`", response = SomeClass::class, responseContainer = "List"),ApiResponse(code = 4XX, message = "General response to all 400 error codes. ", response = ErrorResponse::class),ApiResponse(code = 5XX, message = "General response to all 500 error codes. ", response = ErrorResponse::class)])
    @RequestMapping(
        value = ["/some/post"],
        produces = ["application/json"], 
        consumes = ["application/json"],
        method = [RequestMethod.POST])
    fun doSomething(....) {....}

Related issues/PRs

Suggest a fix/enhancement

If range of response codes is used, generate multiple @ApiResponse with appropriate code from range

Reproduce the issue with the provided OpenAPI YAML and Gradle task using the kotlin-spring generator. Start from the generated Kotlin controller's @ApiResponse annotations and determine how 4XX and 5XX response keys are handled; done means the generated controller uses valid response-code values or clearly supports the intended response range.