Reproduce OpenAPI additionalProperties issue

openapi.yaml

openapi: 3.0.0
info:
  title: MyAPI
  description: MY API
  version: 0.0.0
servers:
  - url: http://localhost:8080/api/
paths:
  /example:
    get:
      operationId: getExample
      responses:
        "200":
          description: "Success"
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Example"

components:
  schemas:
    Example:
      type: object
      required:
        - items
      properties:
        items:
          type: object
          additionalProperties:
            type: object
            required:
              - name
            properties:
              name:
                type: string

package.json

{
  "scripts": {
    "generate": "openapi-generator generate -i openapi.yaml -o src -g typescript-fetch",
    "test": "tsc -p src --noEmit"
  },
  "devDependencies": {
    "@openapitools/openapi-generator-cli": "^0.0.7-4.0.0-beta",
    "typescript": "^3.2.2"
  }
}