Add watchOS support

[lumiasaki]

Hello @mstfy!

While working with some prominent third-party libraries like Realm that offer watchOS instruction set libraries, I noticed that xctrim currently doesn't recognize them. This observation motivated me to enhance xctrim by adding support for watchOS.

Changes Made: watchOS Recognition: The xctrim can now recognize and process frameworks targeting watchOS.

I've tested these changes with several xcframeworks that include watchOS support, and the results were as expected. The tool successfully trimmed unnecessary architectures.

I hope you find these changes valuable. I'm open to feedback and would be happy to make any necessary adjustments.

Thank you for considering this pull request!