title: 'UnityShim' does not exist in the current context
body: <p>How Can I Solve This Error?
  Assets\Inkyu\Assets\Plugins\GitHub\Editor\UnityAPIWrapper.cs(15,18): error CS0103: The name 'UnityShim' does not exist in the current context
  <code><pre></p>
  <pre><code>using UnityEditor;
  using UnityEngine;
  using System.IO;
  using System;
  
  namespace GitHub.Unity
  {
      [InitializeOnLoad]
      public class UnityAPIWrapper : ScriptableSingleton&lt;UnityAPIWrapper&gt;
      {
          static UnityAPIWrapper()
          {
  #if UNITY_2018_2_OR_NEWER
               Editor.finishedDefaultHeaderGUI += editor =&gt; {
                   UnityShim.Raise_Editor_finishedDefaultHeaderGUI(editor);
               };
  #endif
          }
      }
  }
  </code></pre>
  <p></pre></code></p>