title: OpenAPI generator inheritance in version 5
body: <p>In previous version of open-api-maven-generator (4.3.1) I had inheritance with 1 field</p>
  <pre><code> BaseField:
      type: object
      properties:
         id:
           type:integer
  </code></pre>
  <p>and used it to schemas where I needed it like</p>
  <pre><code>allOf:
      - $ref: 'BaseField'
  </code></pre>
  <p>And it was generated as inheritance</p>
  <pre><code>Schema extends BaseField
  </code></pre>
  <p>After version moved to 5. it becomes generated as injection</p>
  <pre><code>Schema {
  // field of BaseField
  Long id;
  }
  </code></pre>
  <p>Is any way to back to inheritance?</p>