title: how i can set icon application in ubuntu with elctron builder
body: <p>
  * <strong>Version</strong>: ^10.6.1</p>
  
  <p>
  * <strong>Target</strong>: linux</p>
  
  
  
  <p>i'm ubuntu user &amp; and i could not set icon for my app.
  this is the error:</p>
  
  <pre><code>No native production dependencies
  Packaging for linux x64 using electron 1.4.1 to dist/linux-unpacked
  ⚠️  Application icon is not set, default Electron icon will be used
  Building AppImage for arch x64
  </code></pre>
  
  <p>and this is build section of  my package.jason:</p>
  
  <pre><code>"build": {
  
    "appId": "985654798458542",
  
    "mac": {
  
    "category": "crm"
  
  },
  "win": {
  
    "iconUrl": "logo.png"
  
  },
  
  "linux": {
  
    "iconUrl": "logo.png"
  
  }
  </code></pre>