title: IApplicationBuilder.UseBasePath odd behaviour?
body: <p>I am trying to add versioning to my web api and after reading asp .net core documentation it seemed that IApplicationBuilder.UsePathBase could serve to this purpose. And, it really does but with a quirk. The api can still be accesed without adding the versioning path.</p>
  <p>As an example, I use this to add an v1 path to my api:</p>
  <pre><code>public void Configure(IApplicationBuilder app, IWebHostEnvironment env, IHttpContextAccessor httpAccesor)
  {
      app.UsePathBase(&quot;/api/v1&quot;);
      ....
  }
  </code></pre>
  <p>Now I am able to access my cars endpoint by using http://www...com/api/v1/cars or by using http://www...com/cars.</p>
  <p>The cars controller routing is setup this way:</p>
  <pre><code>[Authorize]
  [Route(&quot;/[controller]&quot;)]
  [ApiController]
  public class DriversController : ControllerBase
  {
    ....
  }
  </code></pre>
  <p>So, is this how it works? Is there any possibility to just allow paths with the corresponding versioning path?</p>