Could not set unknown property 'useAndroidX' for object of type com.android.build.gradle.internal.dsl.BaseAppModuleExtension : <p>I want to add a library that i've found on github but it required androidx.I found out that i should put these:</p>

<pre><code>android.useAndroidX=true
android.enableJetifier=true
</code></pre>

<p>here</p>

<pre><code>defaultConfig {
    applicationId "com.kolydas.greeksinbrno"
    minSdkVersion 19
    targetSdkVersion 28
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    android.useAndroidX=true
    android.enableJetifier=true

}
</code></pre>

<p>But i got this error</p>

<blockquote>
  <p>Could not set unknown property 'useAndroidX' for object of type com.android.build.gradle.internal.dsl.BaseAppModuleExtension.</p>
</blockquote>
