[in_app_purchase] Update readme.md (#4049)

diff --git a/packages/in_app_purchase/in_app_purchase/CHANGELOG.md b/packages/in_app_purchase/in_app_purchase/CHANGELOG.md
index d41c0d0..52bbff5 100644
--- a/packages/in_app_purchase/in_app_purchase/CHANGELOG.md
+++ b/packages/in_app_purchase/in_app_purchase/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.6
+
+* Added import flutter foundation dependency in README.md to be able to use `defaultTargetPlatform`.
+
 ## 1.0.5
 
 * Add explanation for casting `ProductDetails` and `PurchaseDetails` to platform specific implementations in the readme.
diff --git a/packages/in_app_purchase/in_app_purchase/README.md b/packages/in_app_purchase/in_app_purchase/README.md
index ad28cfa..28b3c08 100644
--- a/packages/in_app_purchase/in_app_purchase/README.md
+++ b/packages/in_app_purchase/in_app_purchase/README.md
@@ -73,6 +73,7 @@
 // Import `in_app_purchase_android.dart` to be able to access the 
 // `InAppPurchaseAndroidPlatformAddition` class.
 import 'package:in_app_purchase_android/in_app_purchase_android.dart';
+import 'package:flutter/foundation.dart';
 
 void main() {
   // Inform the plugin that this app supports pending purchases on Android.
diff --git a/packages/in_app_purchase/in_app_purchase/pubspec.yaml b/packages/in_app_purchase/in_app_purchase/pubspec.yaml
index aa2e8fc..b589c24 100644
--- a/packages/in_app_purchase/in_app_purchase/pubspec.yaml
+++ b/packages/in_app_purchase/in_app_purchase/pubspec.yaml
@@ -2,7 +2,7 @@
 description: A Flutter plugin for in-app purchases. Exposes APIs for making in-app purchases through the App Store and Google Play.
 repository: https://github.com/flutter/plugins/tree/master/packages/in_app_purchase
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+in_app_purchase%22
-version: 1.0.5
+version: 1.0.6
 
 environment:
   sdk: ">=2.12.0 <3.0.0"