I found the cursed garden structure and I located thr boss but the tangled skeleton didnt spawn anywhere in the structure is it a bug?

It'll be fixed in 0.2.2. If you can't wait, try this fixed version. (You can find zipped jars in the action's build artifacts after it finishes building)

And also you have to find a new structure to make the skeletons spawn even if you used the fixed version.