feat!: replace dgeni/gulp with TypeDoc for README generation

Replace the legacy dgeni/gulp documentation pipeline with TypeDoc
and typedoc-plugin-markdown. Generates plugin README files with
extracted @Plugin() decorator metadata. Register custom JSDoc tags
used by plugin source files.

docs/plugins/in-app-purchase-3/README.md

@@ -0,0 +1,45 @@
+# "In App Purchase 3"
+
+```
+$ ionic cordova plugin add cordova-plugin-purchase --variable BILLING_KEY="<ANDROID_BILLING_KEY>"
+$ npm install @awesome-cordova-plugins/in-app-purchase-3
+```
+
+## [Usage Documentation](https://danielsogl.gitbook.io/awesome-cordova-plugins/plugins/in-app-purchase-3/)
+
+Plugin Repo: [https://github.com/j3k0/cordova-plugin-purchase](https://github.com/j3k0/cordova-plugin-purchase)
+
+In-App Purchase on iOS, Android, Windows, macOS and XBox.
+
+This plugin replace the previous InAppPurchase2, due to backward compatibility issue with the wrapped
+cordova-plugin-purchase version 13.0
+
+## Features
+
+|  | ios | android | win-8 | win-10/uwp | mac |
+|--|--|--|--|--|--|
+| consumables | ✅ | ✅ | ✅ | ✅ | ✅ |
+| non consumables | ✅ | ✅ | ✅ | ✅ | ✅ |
+| subscriptions | ✅ | ✅ | ✅ | ✅ | ✅ |
+| restore purchases | ✅ | ✅ | ✅ | ✅ | ✅ |
+| receipt validations | ✅ | ✅ |  | ✅ | ✅ |
+| introductory prices | ✅ | ✅ |   | ✅ | ✅ |
+
+Supports:
+
+ - **iOS** version 7.0 or higher.
+ - **Android** version 2.2 (API level 8) or higher
+   - with Google Play client version 3.9.16 or higher
+ - **Windows** Store/Phone 8.1 or higher
+ - **Windows 10 Mobile**
+ - **macOS** version 10
+ - **Xbox One**
+   - (and any platform supporting Microsoft's UWP)
+ - **cordova-plugin-purchase** version 13.0 or higher
+
+## Supported platforms
+
+- iOS
+- Android
+- Windows
+