title: Adding auth route to generate a JWT in OpenApi 3
body: <p>I would like to achieve this kind of result with ApiPlatform and OpenApi V3:
  <img src="https://i.stack.imgur.com/HoBWJ.png" alt="screen shot of an old swagger displaying an auth route"></p>
  
  <p>I found this on an old SO question : <a href="https://stackoverflow.com/questions/54380730/how-to-add-login-to-swagger-ui-with-api-platform-symfony-4">How to add Login to swagger UI with API PLATFORM (symfony 4)?</a></p>
  
  <p>The route is plugged onto a LexikJWT handler in my firewalls, from security.yaml.</p>
  
  <p>I managed to add a custom thing in the ItemOperations key of my resources.yaml but the thing doesn't seem to map properly to OpenApi. </p>
  
  <p>Am I understanding something wrongly?</p>
  
  <p>Should I drop Lexik JWT bundle and do the auth in an other way?</p>
  
  <p>Am I missing something around schemes or YAML configuration?</p>