title: TypeError: app.makeSingleInstance is not a function
body: <p>Upgrading from Electron v2.0.3 to the latest relase v5.0.1</p>
  
  <p>When I try running electron, I get the following error:</p>
  
  <pre><code>TypeError: app.makeSingleInstance is not a function
  </code></pre>
  
  <p>I believe this is because the api has changed. I cannot find what the equivalent for this would be. Any help would be appreciated!</p>
  
  <p>main.js (was working fine in v2.0):</p>
  
  <pre><code>    let appInstance= null,
          mainWindow = null,
  
      appInstance = app.makeSingleInstance(() =&gt; {
          if (mainWindow) {
              if (mainWindow.isMinimized()) {
                  mainWindow.restore();
              }
              mainWindow.focus();
          }
      })
  </code></pre>