title: Roslyn analyzer/codefix dependencies
body: <p>I'm trying to write an analyzer with codefix and I'm unsure on how I can</p>
  <ol>
  <li>Add a required base class to the consumer project. <br>
  <i>Preferred method would be to have it available at build time only (so generated)</i></li>
  <li>Add the required dependency that this base class has to the consumer project <br>so that compilation of the code fix does not fail. <br> <i> Maybe it's possible to check during analyze phase if that project has that dependency already installed?</i></li>
  </ol>
  <p>The base class is needed by the generated code from the code fix and inherently the dependency of a 3rd party nuget.</p>