1、修复低版本构建错误

Author: BytesZero

example/android/app/src/main/AndroidManifest.xml

@@ -8,7 +8,7 @@
          FlutterApplication and put your custom class here. -->
     <uses-permission android:name="android.permission.INTERNET"/>
     <application
-        android:name="${applicationName}"
+        android:name="io.flutter.app.FlutterApplication"
         android:label="FlutterAds"
         android:icon="@mipmap/ic_launcher"
         android:theme="@style/AppTheme"