title: AutoFixture's AutoData attribute with Xunit throws System.InvalidOperationException
body: <p>I'm using xunit v2.1.0, xunit.extensions v1.8.0.1549, AutoFixture v3.40.0, AutoFixture.Xunit v3.40.0 and I have this simple trivial test that uses AutoData  </p>
  
  <pre><code>using Ploeh.AutoFixture.Xunit;
  using Xunit;
  
  namespace Tests
  {
      public class ToolTests
      {
          [Theory, AutoData]
          public void Test(int foo)
          {
              Assert.NotEqual(0, foo);
          }
       }
  }  
  </code></pre>
  
  <p>And the error that I get in Resharper (v9.2) test runner is  </p>
  
  <blockquote>
    <p>System.InvalidOperationException No data found for Tests.ToolTests.Test
    Exception doesn't have a stacktrace</p>
  </blockquote>
  
  <p>I've noticed that xunit.extensions is not the last version (currently v2.0.0), but when I try to update given nuget package I get error:</p>
  
  <blockquote>
    <p>Unable to resolve dependencies. 'xunit.extensions 2.0.0' is not compatible with 'AutoFixture.Xunit 3.40.0 constraint: xunit.extensions (≥ 1.8.0.1549 &amp;&amp; &lt; 2.0.0)'</p>
  </blockquote>
  
  <p>Any clues why this is happening?</p>