title: Android Studio: No resource identifier found for attribute 'targetSdkversion' in package 'android'
body: <p>Here is the error in my gradle build console:</p>
  
  <pre><code>Error:(7) No resource identifier found for attribute 'targetSdkversion' in package 'android'    
  </code></pre>
  
  <p>I believe this is the code that is causing the error...</p>
  
  <pre><code>&lt;uses-sdk android:minSdkVersion="15"
            android:targetSdkversion="21" /&gt;
  </code></pre>
  
  <p>I've went into properties and set the target sdk version to 21 (Android 5.0).</p>
  
  <p>Any suggestions as to what is causing the error?</p>