title: How to add a content-type on a POST request with no body in OpenAPI 3.0?
body: <p>I am trying to create an OpenAPI 3.0 definition for an existing API. It has a POST operation and takes header values as the input. Request body is empty. However the backend API was coded very poorly and is expecting request header <code>Content-Type: application/json</code> even though the body is empty.</p>
  
  <p>How do I achieve this in OpenAPI 3.0? Looks like <code>Content-Type</code> is not accepted as a valid header parameter in OAS 3.0.</p>