title: openAPI 3.0 is not showing try it out button for API endpoints
body: <p>I've configured my api with swagger openapi3.0, unfortunately, it is not showing try it out button for my API endpoints. am I missing any configuration in the swagger file? can anyone help me how to solve this error?<a href="https://i.stack.imgur.com/MyvKF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MyvKF.png" alt="here is the link to screenshot"></a></p>
  
  <p>Note: I'm using swagger open API3.0
  here is the configuration I've used:</p>
  
  <pre><code>
  {
    "openapi": "3.0.0",
    "info": {
      "version": "1.0.0",
      "title": "Reinvent-API",
      "description": "Reusable and minimalistic API for Hyperledger-fabric Networks",
      "contact": {
        "name": "Dev",
        "email": "dev@gmail.com",
        "url": "https://dev.github.io/"
      },
      "license": {
        "name": "MIT",
        "url": "https://opensource.org/licenses/MIT"
      }
    },
    "servers": [
      {
        "url": "http://localhost:3000/api"
      }
    ],
  
    "paths": {
       "/invoke": {
        "post": {
          "tags": [
        "API Explorer"
      ],
          "description": "invoke chaincode function",
          "operationId": "invoke",
          "requestBody": {
            "description": "body parameters should be passed as the order defined in chaincode function. First argument must be function name to call.",
            "required": true,
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/invoke"
                }
              }
            }
          },
          "responses": {
            "200": {
              "description": "Chaincode Invoke Succesfull.",
              "content": {
                "application/json": {
                  "schema": {
                    "$ref": "#/components/schemas/invoke"
                  }
                }
              }
            }
          }
        }
      }
    },
     "components": {
      "schemas": {
        "invoke": {
          "properties": {
            "fcn": {
              "type": "string"
            },
            "arg1": {
              "type": "string"
            },
            "arg2": {
              "type": "string"
            }
          }
        }
      }
     }
  }
  </code></pre>
  
  <p>Here is the express configuration I've used.</p>
  
  <pre><code>var express = require('express');
  
  var bodyParser = require('body-parser');
  
  var app = express();
  
  app.use(bodyParser.json());
  
  swaggerUi = require('swagger-ui-express')
  
  swaggerDocument = require('./swagger.json');
  
  app.use(bodyParser.urlencoded({ extended: true }));
  var options = {
    swaggerOptions: {
      supportedSubmitMethods:["get", "post"]
    }
  };
  
  app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument, options));
  
  </code></pre>
  
  <p>Or maybe it should be posted to swagger-ui github as a bug?</p>