[Java] Can't genereate code with OpenApi 3 Annotations (Springboot)

Description

Hello, I am using the generator in a java project (Springboot Application) and want it to generate the code with Annotations for openapi 3.0 instead of swagger.
After searching for a longer period of time I could not find any information on how tow do that.
Is there a setting that i can change to achieve this or do i need to use a different version / product branch?

As I use the generated code to generate my openapi 3.0 documentation I struggle with missing information in the endpoint documentation, such as the different responses and codes that i have defined.

If there is anything that is not clear or that i have done wrong in this issue, please let me know. It is the first issue I made and as such might not be too good.

openapi-generator version

Using version 5.0.0 of the "openapi-generator-maven-plugin"

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  version: 1.0.0
  title: ABC
  description: Miscellaneous endpoints for all apps and clients
servers:
  - url: http://localhost:3002/app-gateway-api-doc
    description: local dev server
paths:
  /knock-knock:
    get:
      description: Check connection and get the name of the server
      operationId: knockKnock
      parameters:
        - $ref: "#/components/parameters/language"
      responses:
        "200":
          description: knock knock response
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/KnockKnockResponse"
        "400":
          description: "User not authorized"
        default:
          description: Error
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/RestError"
components:
  parameters:
    language:
      name: language
      description: 2-letter language code
      in: query
      schema:
          $ref: "#/components/schemas/Language"
  schemas:
    KnockKnockResponse:
      type: object
      description: A simple response for clients to check, if the server is online, test,
        if the auth token is still valid.
      required:
        - whoIsThere
      properties:
        whoIsThere:
          type: string
          description: Name of server
          example: Springboot Example, Server xy, v1.0.6
    RestError:
      type: object
      description: Default API error model
      required:
        - type
        - message
      properties:
        message:
          type: string
          description: The error message
          example: There is no resource for path /404
        errorType:
          type: string
          description: Type of error
          example: UnknownResourceError
        additionalProperties:
          type: array
          description: Key/value array to transport additional error information
          items:
            $ref: "#/components/schemas/RestErrorAdditionalProperty"
    RestErrorAdditionalProperty:
      type: object
      description: Key/value object to transport additional error information
      required:
        - key
        - value
      properties:
        key:
          type: string
          example: foo
        value:
          type: string
          example: bar
    Language:
      type: string
      description: 2-letter language code
      default: de
      enum: [de, fr, it, en]

Command line used for generation

Using Maven to build the project.
mvn clean install

Steps to reproduce

1. configure the plugin to use a simple example yaml
2. Do a maven clean install
3. look at the generated Api File and check if the methods have openapi 3.0 annotations or just swagger

Example of my plugin configuration for this.

<plugin>
  <groupId>org.openapitools</groupId>
  <artifactId>openapi-generator-maven-plugin</artifactId>
  <version>4.2.3</version>
  <executions>
    <execution>
      <id>spring-boot-api</id>
      <goals>
        <goal>generate</goal>
      </goals>
      <configuration>
	  <skip>false</skip>
	  <inputSpec>${project.basedir}/src/main/resources/openapi/knock.yaml</inputSpec>
	  <generatorName>spring</generatorName>
	  <configOptions>
            <dateLibrary>joda</dateLibrary>
            <interfaceOnly>true</interfaceOnly>
	  </configOptions>
	  <library>spring-boot</library>
	  <apiPackage>ch.company.project.knock.api</apiPackage>
	  <modelPackage>ch.company.project.knock.api.model</modelPackage>
      </configuration>
    </execution>
  </executions>
</plugin>

Related issues/PRs

Suggest a fix/enhancement

Start by reproducing the Maven generation with the supplied OpenAPI YAML, spring generator configuration, and openapi-generator-maven-plugin versions, then inspect the generated Api file's annotations. Compare the generated Swagger annotations with the requested OpenAPI 3 annotations and verify whether response codes and descriptions are present. Done means the documented configuration or generated output provides the requested OpenAPI 3 endpoint annotations.