title: Cannot resolve AppCompatActivity after updationg
body: <p>in my build.Gradle(app) I updated The appcompat
  from</p>
  <pre><code>implementation 'androidx.appcompat:appcompat:1.4.2'
  </code></pre>
  <p>to</p>
  <pre><code>implementation 'androidx.appcompat:appcompat:1.5.0'
  </code></pre>
  <p>and now the AppCompatActivity won't work and I even returned the old version but still nothing.</p>
  <pre><code>public class MainActivity extends AppCompatActivity {}
  </code></pre>