[in_app_purchase] Configure correct App Bundle identifier (#3883)

By accident the in_app_purchase was committed using the wrong App Bundle identifier (see commit c91c446ac77f68394c29b7dd059f14262b42f059).

This pull request will correct the mistake and update it to the correct App Bundle identifier.
diff --git a/packages/in_app_purchase/in_app_purchase/example/ios/Runner.xcodeproj/project.pbxproj b/packages/in_app_purchase/in_app_purchase/example/ios/Runner.xcodeproj/project.pbxproj
index 0155d79..2de5b9b 100644
--- a/packages/in_app_purchase/in_app_purchase/example/ios/Runner.xcodeproj/project.pbxproj
+++ b/packages/in_app_purchase/in_app_purchase/example/ios/Runner.xcodeproj/project.pbxproj
@@ -427,7 +427,7 @@
 					"$(inherited)",
 					"$(PROJECT_DIR)/Flutter",
 				);
-				PRODUCT_BUNDLE_IDENTIFIER = com.baseflow.example.iap;
+				PRODUCT_BUNDLE_IDENTIFIER = io.flutter.plugins.inAppPurchaseExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				VERSIONING_SYSTEM = "apple-generic";
 			};
@@ -451,7 +451,7 @@
 					"$(inherited)",
 					"$(PROJECT_DIR)/Flutter",
 				);
-				PRODUCT_BUNDLE_IDENTIFIER = com.baseflow.example.iap;
+				PRODUCT_BUNDLE_IDENTIFIER = io.flutter.plugins.inAppPurchaseExample;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				VERSIONING_SYSTEM = "apple-generic";
 			};