patchCraftBukkit caching sometimes fails on macOS

[Jason Penilla]

#60 may have introduced a regression in that on macOS the unpacked build cache entry for patchCraftBukkit is sometimes not a git repo, which causes the task to fail.

Only previously tested on linux where it worked fine.

A possible solution/workaround is to zip the task output

update: seems to work after clearing and rebuilding caches, may be possible that I just had an invalid cache entry somehow? If anyone else runs into this issue please comment.