Added awesome-watchos

I've added awesome-watchos under Platforms,
Is this list mature enough to to be merged?

readme.md

@@ -47,6 +47,7 @@ If you want to create your own list, please read the [create list instructions](
 - [React Native](https://github.com/jondot/awesome-react-native)
 - [Xamarin](https://github.com/benoitjadinon/awesome-xamarin)
 - [Linux](https://github.com/aleksandar-todorovic/awesome-linux)
+- [watchOS](https://github.com/yenchenlin1994/awesome-watchos)
 
 
 ## Programming Languages