title: fonts in XML using support library
body: <p>I want to set fonts through XML fron font resource directory ,but in <code>font.xml</code> file while using <code>app:fontStyle</code> , <code>app:fontWeight</code> and <code>app:font</code> gadle build fails with error </p>
  
  <blockquote>
    <p>/media/shankar/Work
    Drive/temp/BrainColors/app/src/main/res/font/fonts.xml</p>
    
    <p>Error:attribute 'com.color.brain.braincolors:font' not found
        Error:attribute 'com.color.brain.braincolors:fontStyle' not found
        Error:attribute 'com.color.brain.braincolors:fontWeight' not found</p>
    
    <p>Error:/media/shankar/Work Drive/temp/BrainColors/app/src/main/res/font/fonts.xml:0 attribute
    'com.color.brain.braincolors:font' not found
        Error:/media/shankar/Work Drive/temp/BrainColors/app/src/main/res/font/fonts.xml:0 attribute
    'com.color.brain.braincolors:fontWeight' not found
        Error:java.util.concurrent.ExecutionException: com.android.builder.internal.aapt.AaptException: AAPT2 link failed:
        Error:com.android.builder.internal.aapt.AaptException: AAPT2 link failed:
        Error:Execution failed for task ':app:processDebugResources'.
        Failed to execute aapt</p>
  </blockquote>
  
  <p>i did not understand why this heppens while using <code>app:</code> namespace</p>
  
  <p><strong>fonts.xml</strong></p>
  
  <pre><code>&lt;font-family xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
      &lt;font android:fontStyle="normal" android:fontWeight="400" android:font="@font/junegull"
          app:fontStyle="normal" app:fontWeight="400" app:font="@font/junegull"/&gt;
  
  &lt;/font-family&gt;
  </code></pre>