Xcode: Allow embeddeding extensionkit extensions
Starting in iOS 16.1, ExtensionKit extensions are a new kind of extension:
https://developer.apple.com/documentation/extensionkit
These need to be placed in the Extensions/ directory of the bundle, which is done with
dstPath = "$(EXTENSIONS_FOLDER_PATH)";
dstSubfolderSpec = 16;
in the copy files build stage
Example: using the background assets extension apis (https://developer.apple.com/documentation/backgroundassets)
Edited by Russell Greene