title: Generate Swagger json at Build time
body: <p>I'm working on a ASP.NET Core WebAPI project and I'm trying to find a way to generate swagger json at build time ?</p>
  
  <p>As i'm working with 4 environments, i'd like to have 4 swagger.json with a different name of my choice, like:</p>
  
  <ul>
  <li>swagger_{appName}<em>dev</em>{buildNumber}.json</li>
  <li>swagger_{appName}<em>demo</em>{buildNumber}.json</li>
  <li>swagger_{appName}<em>int</em>{buildNumber}.json</li>
  <li>swagger_{appName}<em>staging</em>{buildNumber}.json</li>
  </ul>
  
  <p>Is it also possible to edit the fields in the json ? I'd like to edit (depending of the environment) the following fields : host, schemes and basePath.</p>
  
  <p>I'm using Swashbuckle.AspNetCore but it appears it doesn't have an option to do such task or am I wrong ?</p>
  
  <p>Thanks in advance</p>