Add namespace

Author: nidegen

example/android/app/build.gradle

@@ -16,6 +16,7 @@ apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
     compileSdkVersion 30
+    namespace "flutter.plugins.contactsservice.contactsservice"
 
     lintOptions {
         disable 'InvalidPackage'
@@ -47,4 +48,4 @@ flutter {
 dependencies {
     androidTestImplementation 'androidx.test:runner:1.1.0'
     androidTestImplementation 'androidx.test:rules:1.1.0'
-}
+}