Unwanted conversion from string to integer in examples

[Mcourt]

Describe the bug My examples are being converted to integers although they should be strings (ex: phone numbers). This causes problem when validating my openapi file, as the parameter is set as "string" but has a number as example.

To Reproduce

1. Given this OpenAPI document

   
   openapi: 3.0.0
   info:
   title: My title
   version: 1.0.0
   paths:
   /my/route:
   post:
     summary: My route
     requestBody:
       content:
         application/json:
           schema:
             type: object
             properties:
               phone:
                 type: string
                 example: "0612345678"
       required: true
     responses:
       '204':
         description: No Content
       '400':
         description: Bad Request

2. I execute the combine command
3. I get the following document (Notice the number example)

openapi: 3.0.0 info: title: My title version: 1.0.0 paths: /my/route: post: summary: My route requestBody: content: application/json: schema: type: object properties: phone: type: string example: 0612345678 required: true responses: '204': description: No Content '400': description: Bad Request

**Expected behavior**
I expected my example to stay as a string.

[fabsrc]

This seems to be a bug in the js-yaml package. See: https://github.com/nodeca/js-yaml/issues/530

Tried it with your example:

node -e "console.log(require('js-yaml').safeDump({example: '0612345678'}))"
//  example: 0612345678

Using only digits below 8 (octal digits) seems to work fine:

node -e "console.log(require('js-yaml').safeDump({example: '0612345677'}))"
//  example: '0612345677'