enforce round launcher icon on pre Oreo devices

src/gplay/AndroidManifest.xml

@@ -22,7 +22,7 @@
 
     <application
         android:name=".MainApp"
-        android:icon="@mipmap/ic_launcher"
+        android:icon="@mipmap/ic_launcher_round"
 		android:roundIcon="@mipmap/ic_launcher_round"
         android:label="@string/app_name"
         android:fullBackupContent="@xml/backup_config"

src/main/AndroidManifest.xml

@@ -57,7 +57,7 @@
 
     <application
         android:name=".MainApp"
-        android:icon="@mipmap/ic_launcher"
+        android:icon="@mipmap/ic_launcher_round"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:label="@string/app_name"
         android:fullBackupContent="@xml/backup_config"