[BUG] [cpp-pistache-server] Wrong json include path in api-header

Created by: mpreu

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?

Description

When generating a simple example with the cpp-pistache-server generator the api-header has a wrong include #include "json.hpp" which is not available. The include path needs to be #include <nlohmann/json.hpp>.

openapi-generator version

Checked with

• latest master
• latest 5.0.x

OpenAPI declaration file content or url

openapi: 3.0.2
info:
  title: Test oneof
  version: 0.0.1
paths:
  /project:
    get:
      responses:
        200:
          description: ok
components:
  schemas:
    Project:
      properties:
        code:
          type: string
      type: object

Command line used for generation

java -jar openapi-generator-cli.jar generate -g cpp-pistache-server -i openapi.yaml

Steps to reproduce

Generate with example above and try to compile.

Related issues/PRs

Suggest a fix

Change the include path to correct value.