Switch from support library to androidx.

#1449

Author: Dallas62

android/src/main/java/com/dieam/reactnativepushnotification/modules/RNPushNotificationListenerService.java

@@ -6,7 +6,6 @@
 import android.os.Handler;
 import android.os.Looper;
 import android.util.Log;
-import android.support.annotation.NonNull;
 
 import com.dieam.reactnativepushnotification.modules.RNReceivedMessageHandler;
 import com.facebook.react.ReactApplication;

android/src/main/java/com/dieam/reactnativepushnotification/modules/RNReceivedMessageHandler.java

@@ -10,7 +10,7 @@
 import android.os.Handler;
 import android.os.Looper;
 import android.util.Log;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 import com.dieam.reactnativepushnotification.helpers.ApplicationBadgeHelper;
 import com.facebook.react.ReactApplication;