chore(docs): add external link to SwiftUI Multi-platform example (#1588)

Author: hgq287

Docs/Examples.md

@@ -11,3 +11,4 @@ These are a bunch of real world examples of XcodeGen project specs. Feel free to
 - [pvinis/react-native-xcodegen](https://github.com/pvinis/react-native-xcodegen/blob/master/templates)
 - [covid19cz/erouska-ios](https://github.com/covid19cz/erouska-ios/blob/develop/project.yml)
 - [markst/hotreloading-vscode-ios](https://github.com/markst/hotreloading-vscode-ios)
+- [MultiPlatformApp](https://github.com/hgq287/HGSwift/tree/master/Examples/MultiPlatformApp) - A modern **SwiftUI** multi-platform (iOS & macOS) example featuring a modular 3-tier architecture and shared logic.